The specs look nice for a portable gaming platform, but doesn't seem like anyone's ideal DAP...
So I can't see any reason to port Rockbox to it - the intention (I assume) would be to port lots of existing open source games to it, and that would be much easier if it was running a Linux kernel, instead of Rockbox.
Although "rockbox-as-application" (as discussed again briefly in IRC today) would seem well-suited.