As above, get a cheap MV-1F -- it accepts AES/CD joysticks easily, has a switch and header on the motherboard for stereo audio, and takes up very little space. I got a 1F for about $30-$40, and a couple of multicarts for $70-$100. Heresy, but I don't care.
Of course, this route means you have to make a power supply and video cables/encoder yourself, but is the convenience worth $900?