In addition, there's Cloud42, but while all of these tools, along with Amazon's new official Java API interface are quite nice, none of them (except Rightscale, which is awesome, but very incompatible with what I'm doing, sadly) have any sort of functionality remotely close to properly managing an application launch on the cloud.
I suspect that Nimbus and OpenNebula are actually tools closer to what I was asking about - proper automated system management, rather than just access for manual machine management, however I have not had a proper chance to investigate either of these.
For my purposes we developed our own in house tool using the Typica library and several other tools, that allowed us to give machines abstract names and launch, configure, and issue commands to them via their names rather than instance id's or private dns's. Might be released open source, but that's not my decision unfortunately. I'll update this if it is.