Something much smaller than MercurialBackend. Using just mercurial.revlog which is mercurial backend store. Of course, this will be more like filesystem backend with data and meta stored as compressed deltas in revlogs.
Doesn't have any of these:
- atomic operations without permanent page locking on edit (internal hg file locking) - "many editors, one page" scenario
- easy data backup by cloning
- data synchronisation between multiple instances (branching an merging)
- editable from command line, using plain mercurial (or at least with little help of custom extensions)
but can be bundled with MoinMoin (no external mercurial needed). Looks good enough to be competitor for FSBackend.