I've started building a list of cloud hosting vendors, including those offering platform as a service (PAAS). I'm trying to get vendors to contribute but as yet haven't been too successful. I'll need to directly approach them over the next few weeks to see if they'd be willing to provide me with a few details.
A good friend of mine found a website that lists all cloud vendors. Although it doesn't contain all technology specific information that I was looking for it's quite a comprehensive list and a good starting point. Check out cloudxl.
You can still view my original list too: