Ok, I feel like I'm polluting every thread I touch with this stuff. So, to review:
I want to make an adapter board to go between an "NB" miata (99+) and a MS-II (which natively supports that car).
I want to integrate as many of the functions as I can, so the MS DB37 is basically just talking directly to the CPU.
Anyway, I found this:
http://www.fairchildsemi.com/ds/MM%2FMMPQ2222.pdf - a quad 500mA NPN transistor, which I want to use for running fan relays and even the variable intake coil.
I've been using some radioshack 2n2222 copies (800 mA) and am not sure this would work, but it IS nice and small. Then again, perhaps SMD would intimidate the people I'm thinking would want this board.