I haven’t read this properly but know that recently Amazon have cracked it with relational databases in the Elastic Computing framework. I’ve also looked at Microsofts Windows Azure platform, which has also a lot of great features, generally my heads in the cloud but they are playing catchup.
The future!
http://www.microsoft.com/windowsazure/
http://aws.amazon.com/running_databases/#relational
The particular service I was interested in was http://aws.amazon.com/rds/ now this is friction free deployment. It is positively slippy.