VP 0.9.4 version up. I added support for nested groups, along with modifiers, for easier organizing complex scenes. Also added a simple palette feature for the project colors. I'm using it already for several illustrations and it's very powerful to plan a scene and have grids and composition ready.
SomaVanishPoint tool is now on v0.7.1. A lot has changed. See thread for more infos. This tool is now very powerful and too good to be free. There's nothing comparable out there. artbuddy.urlich.ch/vpoint/