This is fine if you do all your development in the cloud but what if you want to do local development and then parcel up your vm and load it up to the Rackspace cloud...
Just sayin'.
OVF - open virtualization format multi-file format.
OVA is OVF tarred up
Do you know any cloud provider that allows you to upload OVA?
Sadly no. I think any that do support that are in a pricing tier above what I would be willing to pay.