I would like custom backplates for wedge Amigas (mainly A1200) for easier tower builds, pre-cut plates would rock, make a hole in the back of any ATX case then people can pick how they want to put it in place.
I would also want a flexible Riser for the expansion ports on wedge Amigas, so you can mount accelerators a lill more where you want it also it would rock to be able to flip the card around, some cards get's more space if you where able to turn it around!
Edit: I would also like a custom keyboard case for wedge Amiga keyboards, so you can use a Wedge keyboard for tower builds or for bigbox Amigas, it's quite easy to get hold of spare keyboards.