It's quite different from Heroku. With Heroku you're deploying your app to a foreign hosting service. With oncloud you're running it locally while making it accessible publicly. No need to push anything anywhere and you have full access to your local filesystem.
Great idea. Was looking for something like this to show some prototype. Was wondering is it necessary to be restricted only to rails app? For ex., I can host a wiki and try to get static address with your service. Might want to check dyndsn sort of services.
I wonder what kind of latency hit you get from routing your requests through a proxy and more importantly how long the polling delay of the BRIDGE requests are.