Last week Webbynode announced that they have added Spree as a "one click install" option to their "ReadyStack." The ReadyStack is probably one of the more interesting features provided by this up and coming Rails hosting service. The Webbynode home page contains a great video explaining more about how the service works.
The Spree wiki has also been updated with a brief guide on Spree Installation With Webbynode. The installation process is actually relatively simple, the wiki is really more to give you an idea of what the process looks like.
Unfortuantely due to the overwhelming demand for Webbynode, they are temporarily sold out of new server instances. It looks like you will need to wait about a week before being able to try this service out. In the meantime, you can checkout a live instance of Spree running on the very modestly priced "256" plan. I don’t have a lot of experience running Spree is such a low memory environment but it does seem to run well under modest load conditions.