I'm currently planning on using mojosetup (Sorry, gang- logistics on trying to support all the differing packaging systems is going to be EVIL...), which while it makes it a non-participant in your packaging systems, it is one of the nicer compromise plays in that space. Moreover, the game's not big at all- it can comfortably be re-installed on multiple accounts without any appreciable pain involved.
Will there be a way to extract the files out? If that's the case, I'd probably like to write an ebuild that'll put it into /opt/caster (binary-only directory), and all other files appropriately (locale, save games, kde menu icon, etc). Probably work on it after the beta's closed.