Yes - I got my iMac running MAME and managed to get my xbox 360 controller working with it as well. All I need now are a USB trackball and paddle controller and I'll be happy!

Can't get pacman to work though :-( But I haven't played MAME much for years. Glad to see it's still coming on. My little lad has even got into Wonder Boy and Bubble Bobble.

you can get a USB thing that you can plug real Atari controllers into, like the bets paddles ever made. Don't know if it works with a Mac though.

Can't you just get a normal USB trackball, like a mouse replacement? Dunno if any have a top facing trackball; the last I saw all had them on the side where your thumb sits.