Replace Dying Xbox With SFF Atom System, XBMC and Emulators?

I have what is probably a pretty standard set of requirements. The scenario: I have an old Xbox which we currently use for watching movies and playing emulators. Problem is, its dying. Also, the lack of HD playback capabilities is getting lame, particularly when we have a bunch of HD capable computers on the network so our collection of HD content is growing.

Anyone have ideas with regard to an HD-capable system that can also do MAME? We're used to the old Xbox, so our standards are kinda low

Any thoughts on using one of the newer ION / ION 2 systems for emulation play?

I'm not well versed with emulation, nor have I tried on my xbmc box, but check this thread.
http://forum.xbmc.org/showthread.php?tid=73428

I have the Acer Revo 1600, and it's a capable little ION machine!

for most emulators an Ion system should do just fine, but I would consider a dual core atom (e.g. 1st gen 330)

I'd suggest Advanced Launcher

I have NES, SNES and Genesis emulators running on an old P4 2.8ghz with XBMC / Ubuntu. I can't say I've ever seen it stutter or get bogged down while playing. I'd think any of the ION / ION2 based systems should be more than capable.

Only problem I've had is that I couldn't find a nice front-end to integrate into XBMC Linux. I've been using wahcade instead (closing XBMC when we want to game).

I've been following the Advanced Launcher thread that rausch linked above. I'm hopeful that this takes off and continues to see active development. I can think of a couple similar projects that fizzled out in the past couple years that also looked promising at the outset. Here's hoping this one works out - the scrapers integration looks excellent!