only difference tween the tiny and the arduino is memory space which I dont need, and program space (which I am using 1kb less than half of the tiny's space), io pins(have enough extra now), and hardware capabilities like hardware ttl serial, which if I get desperate 1 quick command enables jtag
also the arduino sits on my desk all the time, so no big deal there
turdley even if I wanted to use the arduino the 2 second bootloader gets in the way, by the time that starts up your into a ton of polls since system startup, using a "near zero" bootloader gets you into about the 16 range @ 8mhz, using no bootloader @ 8mhz I am syncing up with the signal at 9 polls in, for hardware that is usually sitting there anyway
as I replace arduino code with standard avrgcc code I am currently syncing up with the signal 7 adb polls in, and there is a lot of things still to work on, including structure and flow, I need to hit like max 2 polls in before the keyboard is required to respond, # 3 is the mouse, then I have lots of free time
if I get cheap about it I can just add 3 parts and crank it from 8MHz to 16-20MHz in seconds
edit: also keep in mind this is currently sampling the signal from the mac host and synthesising a response, before I go adding more stuff I may write a new core and use precalculated tolerances, this is the way the original hardware handled it, well that and lots of assembly code