Well why not get a real arcade pad and mod it to work with a ps2.
Channel Beat has one that you can purchase. I just dont know how many they have if any, but the pad is $195 and there is an upgrade kit for $195 as well. so you can have a functioning pad that is in fact a real arcade pad if you are willing to pay 2-5 times the price of a pad made for the ps2. And some decent soldering skills couldnt hurt on making something like this into something useful.
http://channelbeat.com/products/part...parts/130.html http://channelbeat.com/products/part...parts/131.html