1) An RTG solution for the A1200. maybe a small pcb that fits between the mobo and the accelerator board.
2) A cheap USB solution for the clockport.
I second this, but for the A2000 as well. A USB card would be very useful for users of A500, A600, A2000, and A3000. That may be where you want to start. Zorro ethernet cards will also be in demand.
First preference would be the following:
1) A new 60860 accelerator with 1 or 2 gigs of RAM and an integrated P96-compatable RTG card with > 4 megs of RAM with a fast bus to the proc.
...if that is not possible, the following would be nice:
2) A new 68060 accelerator with 1 or 2 gigs of RAM.
3) New Zorro II and Zorro III RTG cards with > 4 megs of RAM.
...the end goal should be to give classic Amigas enough power to browse the web, hence the push for 060 accelerators and RTG cards. These expansions are in demand and often sell for hundreds of dollars online, so there is an incentive in creating them. Also, the Amiga community should fund a bounty for a native port of Netsurf. Again, the goal is to get classic Amigas surfing the web and at higher colors and resolutions.
If you do take a stab at creating a new motherboard, please target the layouts of the original systems and not new PC cases. Much of the joy of owning a classic Amiga is in keeping the old girls up and running for as long as possible. An new motherboard in a new case is a new machine.