I know that this is a bit exaggerated, because i got stuck writing a "real" VCS plugin with the MSSCCI interface. So i wrote a command-line wrapper that serves most purposes (just moving a file is not possible).
See http://www.intellij.org/twiki/bin/view/Main/SourceOffsite for plugin description and download.
Works with 4.5.x and Irida.
Just tested with the SourceOffsite 3.5 command line client, not the 4.x one.