Homebrew PCBs

> In my ongoing research to make a UV exposure box the Right Way, I come to 
> the question of the tubes.  Where is a good place to order 12-inch T8 
> tubes that emit the right wavelength.  According to 
> http://www.turbokeu.com/myprojects/pcb.htm, a Sylvania 350 blacklight is a 
> good match, but I can't find much on this through google, particularly if 
> it's available in a 12-inch version.  So, what are my options for 12-inch 
> tubes?

Do you need it only in 12-inch?
A recommended and tested tube for many years has been F15T8BL, but in 18 inches.

http://www.lightingsupply.com/F15T8-BL.aspx

You could look for any replacement for several manufacturers. You just only need to specify that the tube will be a F15T8/BL or /350BL equivalent.
Do not use a BLB since it includes a filter. Also avoid any "bug-zapper" or fancy "disco-party" black lights since include some painting/colouring that may change their properties. Remember, you need a bare-bones, simple UV light with 350nm. And also avoid U-shaped tubes, since you want uniformity along all your surface. If you use a U-shaped tube, there is more concentration of the light in the "U" than in the other part of the tube.