I don't think you'll run into much anger here, at least from the people who've been here awhile.
Most of the people are genuinely curious, and are still trying to figure out why you would CHOOSE to go a more difficult route, given all the obstacles YOU are presenting, in addition to the ones presented by others.
That's good. It's easy for disagreement to turn into conflict on-line. I guess I'm a fine example of that.

I should have more faith in you guys!
Trimoor: Sorry I jumped the gun, I guess I didn't understand what you were saying. I don't know the technical details of the existing keyboard encoders. I don't know if they are on PICs (and if they are on PICs, they'd probably be the older, one-time programmable ones, which were the only USB PICs until recently.) If they're not PICs (but rather some other kind of microcontroller) then I currently have neither the hardware nor expertise to re-program them. Plus if the circuit weren't set up for in-circuit serial programming I'd need to pull the chip to re-flash it, and that would be a pain.
But in any case, it just wouldn't be worth the cost. It'd cost at least $30-$40 to get the pre-made USB keyboard encoder, and for that much money I could buy all the parts myself and then some. In terms of wiring it's a very simple circuit: hook up a USB connector, a crystal, and 20-30 screw-in terminals on a general-purpose board and it's good to go. It won't be as pretty as a custom-printed or custom-etched circuit board, but cheaper and probably easier to work with.
I do generally share my source code. I don't know how much I'll have to write for the encoder itself, unless I decide to make it support re-mapping the buttons.