Well, it looks like DO is the likely option for hosting.
My system plan requires a simple character sheet/data repo, XP tracker, and die roller. Those are the only "non-standard" elements I need to get the game off the ground. It looks like those can be done in any codebase. If there's anything to drop in for M&M, it would make the decision pretty much automatic.
I do want a nice wiki interface, I admit to rather liking those.