[ownedthx]

Apache Ivy is built on Java and could be a starting point for the uber package manager. It is extremely extensible and can resolve depencies against maven style repos, file systems, and really any other storage mechanism. It can resolve against multiple repos simultaneously.

The real problem is that its so powerful and hard to ramp up on... The docs aren't sufficient for its overall complexity. That all aside, if the will were there, it could be the git of package managers.