Does anyone know if there is some company I could send off a schematic of the adapter he uses and have one sent to me? (This would be UK, but I have no idea what term I'm searching for to get a single circuit board made)
Batch-PCB ( http://www.batchpcb.com/ ) takes longer (they have the boards made in china, at a reputable manufacurer), but cheaper.
Itead Studio ( http://imall.iteadstudio.com/ ) China, Very cheap (they buy empty spaces in fabs, you get 5 (or 10) PCBs buts its possible that one or two arent working.
Bilex-Lp ( http://www.bilex-lp.com ), Bulgaria I think.
Multi-CB ( http://www.multi-circuit-boards.eu/ ) I think they are a british company.
I have no personal experience with any of those companies, though. Small batch PCB manufacturing is always expensive. Get in touch with a local hackerspace and etch it yourself ;-)
http://www.ladyada.net/library/pcb/manufacturers.html
You'll have to buy the connectors and solder them on yourself.
It sounds like an adapter kit might have a little market when shipped with a displayport plug, a small power supply, and a fully assembled PCB. Small kickstarter?
Just FYI, those SMT flexible-printed-circuit connectors are a bitch to get soldered onto a PCB correctly. You might survive with a lot of flux and a very thin tip (and a microscope since the plastic will melt at a pretty low temp. No mistakes allowed).
You might do a little better with a hot air gun. But this is not level-1 soldering.
From what I gather the boards are actually made by Amitron outside Chicago.
Unlike most quickturn PCB fabs they don't bury you with options. The standard options give you everything you need (ENIG, double mask+silk screen, either 2/4 layer, etc.). The OSH Park ordering wizard is a case study in how PCB orders should be done, and for the quality the price can't be beat. Best of all, it's just a "Fred in a shed" operation in Oregon that came out of a hackerspace there.