Major Description
The type of the 'id' field is different (<str> for rackspace, <int> for linode) on Nodes returned from the list_images() call.
I posted this to the mailing list and apparently there is not a standard type for 'id' across drivers.
The unit tests seem to initialize nodes with integer 'id' as well.
They should all use the same type for the id field – presumably string since there are providers that use strings that cannot be converted to ints.