Check out zero-install.fs.net & rox.sf.net (Score 1)

I stumbled across this a couple of years ago - Zero-Install (and the Rox Desktop) at Sourceforge.net. Zero-Install is similar in effect to Bundles, but have the added effect of being installed on demand and shared by all system users - think of it as an Application Cache that you control the "expiration".

http://zero-install.fs.net
http://rox.sf.net