I have committed the Perspective extension from our patch tracker. Like Envelope, it morphs one path to fit another path with 4 nodes, but it does it differently using with perspective distortions.
One thing it requires is the Numeric Python package. Since we're carrying our own Python on Windows, can we add it to the package too? Otherwise this extension is unusable on Windows.
There are more issues with this extension, such as it not working properly for me :)
http://sourceforge.net/tracker/index.php?func=detail&aid=1600298&gro...
Also it displays a window with some Python/Inkscape warnings after it is run. However I decided to commit it, since being an extension it will not destabilize the program, and because more people will find it and test it and hopefully fix it.