I found this thing at Electronics Boutique at the mall. It's the best of both worlds (and it's $7).
It's a gamepad that can be plugged into the ps2 connector on your pc and has a keyboard passthrough (like an ultimarc device). If you don't mind a bit of a solder job, it's much much cheaper than an Ultimarc with all the functionality (Plus a couple of extras).
Plus the thing is programmable with something like 20 or so buttons. All the programming is done through the controller itself - no software necessary. The manual and instructions suck, but that can be overcome.
I bought one to take apart and play with since it was so cheap. Haven't decided if I'll use it yet or not. Sure beats a traditional gamepad, though, because you can use it outside of games (if you want to). Plus you can program in full key sequences (up to 5 keystrokes), not just singular keystrokes. Plus you don't have to reconfigure MAME to work with a gamepad since the computer recognizes it as a keyboard.
I left it at my fraternity house (where I've been working on my machine) so I don't have the name on me, but I had never heard of it before. Has anyone else seen this thing? It's a good way to save a few bucks if you dont' mind doing some work yourself. (Plus if you need to add any commands that involve multiple keystrokes, this would be much of an option with an Ultimarc.) Maybe this is old news, maybe not.
P.S. Don't get me wrong. I have a J-Pac and I love it, but this might go into my next MAME machine.