I'd hate to rip apart my classic Atari paddles though. I might measure the pots inside them, and see if they are the same resistance - then I could just have a couple of Atari-style plugins on my cab somewhere, and plug them in when I want 'em. Or I could just put four pots and four buttons on a little metal panel, and get knobs for the pots, that'd be just as easy.
I think you can get four joystick axes out of a PC gameport pretty easily... but it's been a loong time since I've even glanced at a gameport spec. I think all you have to do is wire the pots to some of the pins, and it's ready to go.