I guess I'm ancient, as I'm actually aware of Mojo Nation 
Zooko et. al. were talking about implementing accounting a while ago for their more modest successor project, Tahoe-LAFS, though I'm not sure if they're still planning to do that.
The subject came up on this forum a couple years ago, although it was in the context of generic file storage: https://bitcointalk.org/index.php?topic=86384.0;all Zooko et. al. were talking about implementing accounting a while ago for their more modest successor project, Tahoe-LAFS, though I'm not sure if they're still planning to do that.I remember emailing Zooko about it back then, but nothing really came of it.
Maybe it's better to look at a rebooted MojoNation as a replacement for Bitcoin's P2P layer which might incidentally turn out to be useful for generic storage too (maybe for all that extra data people want to stuff in the blockchain?)