An alternative which may or may not suit is to buy commercially available analogue joysticks / joypads (from $fckall on ebay china, or from the games store) and replace their analogue input components with your own, or just rip the main PCB out and transplant into your hardware.
You'll need to match some of the electrical characteristics, but the hard work of coding/USB comms etc. is done for you and usually the comms protocols / input mapping is well known.
Chinese knock-offs of PlayStation-style USB controllers etc. can be had for a few bucks, which is well below the price of hobbyist *duino IO boards etc. and cheap enough to be disposable when you blow the first one or two up.