We are currently in beta testing right now. You might want to check it out:
* iKnode (http://iknode.com)
If you like an invite, just signup here: http://iknode.com/register/
If what iKnode offer doesn't match what you are looking for, don't dismiss the idea of a Backend as a Service just yet. Try the following as well:
* Parse (http://parse.com)
* Kinvey (http://kinvey.com)
* Stackmob (http://stackmob.com)
Among others...
EDIT: Fixed the Kinvey Link.