Engine Yard, which closed on $15 MIL of funding mid 2008, is extending its Ruby on Rails stack to Amazon's AWS platform. Amazon participated in this funding. Engine Yard has also developed Solo for deploying services. Most importantly, they unveiled Vertebra to run distributed applications across many servers. I think Engine Yard is ahead of the curve right now and hope they survive. Sometimes (I've been through this personally) you're in a startup too ahead of the curve.