I take it you are aware of the VCS package already on CPAN. A nice system that integrates with cvs, rcs and hms. Its only a read-only interface right now and there development is a little slow. However they do have a sourceforge entry and a Mailing List.
in reply to RFC: proposed new module VCS::Lite
As for your plans to build a self contained VCS system. Will it not suffer from the fact that its storage will be proprietory or are you planning to interface to a more widely used system as a backend?
Remember that amateurs built Noah's Ark. Professionals built the Titanic.