> TOTD used two stock Dreamcast keyboards (of course), which are fairly cheap on eBay > still They're essentially a PC-104 keyboard that speaks Maple bus instead of XT or AT > or PS/2.
a little off-topic, but i purchased typing game for PS2 about 10 years ago - Beatmania Da! Da! Da!
it came with Konami USB keyboard which is fully compatible with PC.
i use this keyboard on my PC thru these years and it's still working fine.