If only it were that easy...
Ultimately, one of the two would have to give up on their OS (I cannot see merging the dev teams working). Hyperion wouldn't let AmigaOS stop development, that's for sure, and while I've no idea what the MOS devs would think I'd imagine that it would be similar. Hardware-wise there would probably be more luck (maybe even just joining forces to obtain higher quantities of PPC processors at lower prices) but there's simply too much mutual distrust for it to work IMO.
BTW it's Genesi - Genesis is a TCP/IP stack ;-)