My Minimig arrived today (a big thanks to Matthew at AmigaKit!). After installing the case I'd purchased a bit ago I tried to boot my new prize. I attempted to use the ROM files and key from the latest Amiga Forever 2008. No boot. After finding my Amiga Forever v 2.0 CD I copied those files to the card and the Minimig booted perfectly! Very nice.
So, looks like the new AF2008 rom files aren't compatible.
For those who wonder whether to get a Minimig...wow, very cool and appears to be highly compatible so far.