recommendations for efficient offsite remote backup solution of vm's

This might not be possible in your situation, so I hope I don't get down-voted in that case, but it might be more efficient to change your backup strategy. If you back up specific data instead of VM snapshots, your backups would run much quicker, and it would be easier to capture changes.

Depending on your VMs and what they're used for, you can just have them back up data to where you store the snapshots now daily (or whatever schedule is appropriate), and then JungleDisk can back up just the data. That would more efficiently transfer changed files, and the space required for backups as well as time needed would be reduced. In addition, you could still take snapshots to retain, and just do that much less often (weekly, for example).

In this case, you could always just bring up a new VM and restore data, or use an older snapshot to restore the VM, and then use the data backup to restore to the most recent point.