I've been using rPath linux images on EC2 built with rBuilder Online.<p>As long as you don't try anything interesting it works pretty well, but beware: there's a steep learning curve when you get to conary, cvc, groups, shadows, changesets, recipes and builds.<p>It's also nice that conary is open source. Unfortunately it has some pretty hairy linux/elf dependencies which prevent me from using it on OSX.