Moved to GitHub recently and seen some more development (features):
Links below still work, but are pretty much deprecated (subversion repo is not maintained anymore and will probably be put down):
Not much there yet
last touched 1 year ago
http://github.com/mdarby/restful_acl/ - google code too -
Just does REST? More of an app than a plugin.
“Lockdown stores an array of access rights in the session”