Great, thanks! Here's a few details about what I'm looking for:
The graphics are in 16 colours (effectively 15 - colour zero isn't used for sprites etc and I'd like to save it for some sort of copper gradient for the background).
Unlike the ones I've drawn, I'd prefer the player sprite to fit into 16x16 pixels, with some animation frames to show him walking and one for falling (check the YouTube link to the Jaguar game for a guide). I'd also need a second player but you could probably just use different colours for that.
The platforms are 8x8 pixels and only use three components - a left edge, a right edge and the 'centre'. It should be pretty simple to come up with some different designs and patterns to inject some variety.
Lastly some bonus fruit pickups (preferably also to fit into 16x16).
Obviously there's also the issue of title/presentation stuff but that can wait for a while I think.
(If anyone's interested in doing music, I'd like a couple of reasonably short-ish tracks in .mod format, one for the title screen and one for the main game. I'd like to load all the data in one go so there'll be no disk access during the game so I don't want large samples etc. And the sound effects shouldn't be too hard, I only really need a sound to indicate an item has been collected and a death sample, maybe one for each player.)