Cloud computing - or at least all the talk about it - is causing IT vendors to change their pitches on the off chance that cloud could actually end up generating some money. And to that end, rPath - founded several years back on the promise of open-source appliances and an application packaging environment - is shifting gears …
I tried rPath & rBuilder a while back
It's all very well as long as you stick to exactly what someone else has already cooked up.
Try modifying the repositories or adding your own stuff and there is a world of hurt there. In the end, I found it easier to port applications out of the rPath repo onto RHEL than to get stuff working with Conary.
This sort of sausage-machine builder is already available for various architectures - that's what RH's Kickstart is all about., for example. rBuilder offers a neat-looking interface to such things, but the amount of effort behind the scenes mecessary to support this is excessive.