I really like the idea that you could use something like an iPad. (or better two iPads) rest your hands on the screen in what are your natural "home row" position. Then touch type text that appears on a screen in front of you while the iPads are busily figuring out how far your fingers are moving and 'tuning' where the other keys should be done. Once you've done like 50 words error free it beeps and send that off. Shapeways makes the cover, Albert PCB makes a circuit board, and you order key switches and diodes from a distributor. Boom a custom keyboard designed by you for you.
Could you ballpark what the cost to build one would be?(ignoring tools like the soldering iron?)
Keys - $0.80 x 78 Diodes - $2-$3 3D printed shells - $240 from Shapeways. Cheaper from a friend with a makerbot Keycaps - Cheapest when harvested from a board found at goodwill. Otherwise, $35 or so from WASD Teensy++ - $24
I'll leave the "priceless" joke to the peanut gallery.