Glassblowing tools:

Wale Apparatus - Torches, graphite tools, oxygen generators, etc. This is where I purchased all my glassblowing tools. They sell a scientific glassblowing kit, and are flexible enough that they allow you to add/remove items and retain the 10% kit discount. They also supply borosilicate glass tubing and rod.

Glass and glass based products:

Voltarc Masonlite - Where I got lead glass tubing. The tubing comes as 50lbs boxes (except for 25mm tubing, which comes in 30lbs boxes). They do not sell directly to individuals, so I had to purchase it through a neon sign supplier (but picked it up at the factory in Orange, CT). The glass itself originates from Osram Sylvania in Kentucky.

SCHOTT

Vitta Standard Glass Transfer Tapes

Taizhou Sunflex Industrial Co.,Ltd. - a cheap source for solder glasses originating from China. I have not tried their glass, but it is significantly cheaper than solder glass from SCHOTT.

Wire (glass to metal seals, filaments, supports):

ESPI Metals - A source I used for kovar wire. They do not sell to individuals, so you must order through a company or educational institution.

JLC Electromet - Dumet, NiFe, nickel

MWS Wire Industries - Supplies Dumet, nickel, tungsten, molybdenum, platinum, etc. Their quote to me for 50 feet of Dumet (minimum quantity) was on the pricey side.

Neon sign components:

SVP Neon - Their electrodes use lead glass from Osram Sylvania in Kentucky.

Gases:

Spectra Gases Inc.

Classes:

Scientific glassblowing is a dying art in the United States. The only school in the US to offer a degree in scientific glasswork is Salem Community College. Basic classes are hard to come by, especially as universities (unwisely) close their glass labs for budget cuts. I was fortunate enough to be able to take an introductory course by glassblower Daryl Smith at the Yale Scientific Glassblowing Lab (there are no intermediate level courses). The course is offered to a maximum of 5 students per class (sometimes with 2 class sections per semester), and chemistry graduate students have first priority for getting these spots.

Vacuum Tube Workshop - Located in Carlsbad, CA, this is a new workshop where for $350 you will build a triode.

Scientific glassblowing links:

The Scientific Glassblowing Learning Center - Tutorials by Joseph W. Walas, retired East Carolina University scientific glassblower.

Forums:

diyvacuumtubes.com - A forum dedicated to DIY vacuum tubes. New as of 2016, this forum is the first that I know of dedicated to this subject.

Links to other homemade vacuum electronic devices:

The following are links to every site I could find on the internet containing homemade vacuum electrical devices (lamps, diodes, triodes, CRT's...). If you know of any more, let me know!

http://www.youtube.com/user/glasslinger/videos/ and http://tubecrafter.com/ - There are a number of very useful and detailed videos by Ron Soyland on YouTube under the username "glasslinger", where he demonstrates and explains the construction of various vacuum tubes and glassblowing techniques. He also has a website explaining his tools and techniques.

http://paillard.claude.free.fr/ (French) - Contains an excellent 17 minute video showing the steps Claude Paillard uses to make his own triodes. The site also contains what looks to be a lot of useful information, so it's probably great if you speak French, however I find it hard to understand much of the site using Google translate.

http://www.tubedevices.com/alek/ (Polish) - Aleksander Zawada makes number of handmade vacuum devices, including diodes, triodes, tetrodes, ion gauges, neon and nixie tubes, Crookes tubes and more. The site is mostly interesting to look at, but unfortunately not much information is given on how anything is made. The site is also a bit disorganized and hard to navigate, but still worth browsing. There is an English version of the site, but it is missing some of the content of the Polish version, and also has a few broken links, so I prefer to navigate the Polish site within Google translate. There is also an article (in English) about his tube shop at http://lekernel.net/blog/2011/09/prywatna-wytwornia-lamp-where-diy-meets-vacuum-electron-devices/.

http://www.jogis-roehrenbude.de/Leserbriefe/Ruediger-Walz-Seite.htm (German), and http://www.radiomuseum.org/dsp_multipage_pdf.cfm?pdf=tube_self_construction.pdf (English) - A chemist by trade, RĂ¼diger Walz describes his building of replica early 1920's tubes starting in the 1980's along with his friend, Franz Pemmerl.

http://www.teralab.co.uk/Glass_Blowing/Glass_Blowing_Menu.htm - After learning some basic scientific glassblowing through reading a few books and experimentation, Robert Hunt describes a number of techniques he uses to produce a number of incandescent lamps, a diode, triode, photocell, CRT, and a few other devices. He also describes the materials used, and has a few videos demonstrating fabrication.

http://hackaday.com/2014/11/21/artisanal-vacuum-tubes-hackaday-shows-you-how/ - A short article on homemade vacuum tubes by Charles Alexanian.

http://www.oldatheart.co.uk/hometriode.html - A homemade triode by Gerry Wells, curator of The British Vintage Wireless and Television Museum.

http://www.sparkbangbuzz.com/ - While he uses absolutely no glassblowing (none of the devices would work without a continuously running vacuum pump), Nyle Steiner makes his own crude (but functional) diode, triode and a number of CRT's. The rest of the projects on his site are also very interesting.

http://www.hpfriedrichs.com/bks-ioa.htm - H. P. Friedrichs writes about his homemade triodes, among other types of amplifiers, in his book "Instruments of Amplification". I have not read the book, but from the photo gallery on his website it looks like the triodes are in the same style as Nyle Steiner, not utilizing any glassblowing and requiring a running vacuum pump be connected in order for the triodes to function.

http://imajeenyus.com/vacuum/index.shtml - Lindsay R. Wilson explains how he makes Houskeeper seals, and demonstrates a thermionic diode under a bell jar and a Panaplex display in a jam jar.

http://dalibor.farny.cz/ - In this blog, Dalibor Farný documents his progress in attempting to produce nixie tubes.

http://www.fusor.net/board/viewtopic.php?f=10&t=3706&hilit=hysol+respect#p21114 - A forum post by George Schmermund on using epoxy in high vacuum work where he displays some homemade triodes using epoxy to form glass to glass seals. Information on triode performance is not given, and I'll admit I'm skeptical about using epoxy to form a seal in a vacuum tube.

http://www.toptinkers.com/ - Oliver Snowdon shows several attempts at making diodes, having some success at the end.

http://www.incandescentsculpture.com/ - While more artistic than scientific, this site displays a number of incandescent lamps hand-blown by artist Dylan Kehde Roelofs (many of which are for sale).

https://www.youtube.com/watch?v=gOTaV6YAIME - A short video of someone showing off some of their initial attempts at incandescent lamps using Dumet wire and soda lime glass. None of the bulbs are evacuated in the video, and no updates have been posted as of January 2015.