Personally, I have been looking at getting a PPC for my 3000 so I would like to see a resonably priced one hit the market 
Yep... A CPU Card PPC for A3000/4000. Heck, even at a high price, it'd probably be a decent seller. Dodgy 3rd and 4th hand ones go on eBay for hundreds. I'd probably be willing to pay a few hundred for a one that was tested solid, but right now, there are so many defective/damaged ones on the market, who knows if one is good or not? I'm not really willing to roll the dice on odds that bad. The new solution needs to be compatible with the current PPC software, though.
Other projects I think would be cool.......
1) Amiga RGB -> Component Video adaptor. I commented about this in a post here about Plasma TVs a few days ago. As the idea kept rattling around in my brain, it kept coming back as a fairly simple thing to do, and would be a welcome addition. Maybe tack an S-Video plug on it, as well. Should be able to fit a form factor similiar to an A520 TV adaptor.
2) Along the same lines, I have another problem. I use an A1200 for games. I have an NTSC only television that I like to play games on. Most games swtich to PAL. Television then refuses to display. So... A gaming-priced PAL/NTSC converter would be useful. This could probably be marketed cross-community, because PlayStation2 importers and such run into the same problems. All too many TVs in North America are NTSC only.
So, how about it, sirs?