I'd love to see a 1200 form factor machine, except with USB instead of ser/par ports, HDMI instead of 23 pin video, (Heavily implying Jen's fantastic flicker fixer built in!) and a DVD player on the other side of the case-original floppy drive intact for old games, or at least the header on the board to hack the connector in. Oh, and wifi, ethernet, or both.
For most people's old school game needs, an 040@40MHz is more than enough, just give it 256MB RAM or else a laptop DIMM slot. Make it $200, with modern connectivity, and full AGA/old game compatibility.
The 1200 was just the right size, and today's electronics make the case hugely roomy.
I've already got other computers with tons of CPU power, I just want an 'Amiga' that I can plug into a modern television, get on my LAN, and have enough browser (OWB) to find those old games and get my retro on :-) Haujobb demos on big screen yummm!!!