Probably using USB pads things would be a lot easier, but I guess I wouldn't end with the same inputs/price ratio.

I'm sure the I-Pac is a far better solution, and maybe I'll use it in a future project... but for now, since it's my first atempt to build arcade controls for my PC I'd like to keep costs as low as possible.
Here where I live I can buy so called "original" (I doubt it) digital PSX Pads (not the analog, dual-shock ones) for less than US 5 dolars. These seems to work very well with all "variations" of the DirectPad-Pro drivers.
Well, I'll give it a try them... all I need now is some free time!

Thanks everybody for the great feedback!