Choosing the right product

I have a dozen clients or so who use Acronis Universal 11. Each client backs up their server on a local NAS device. For each client the Windows 2003 server runs inside a virtual machine on a local ESX4i server.

This works great but they need to manually swap hard-drives in the NAS unit (built-in hot swappable RAID1) to have an offsite copy.

I'd like to offer a solution where I centralize their backups onto my own network so that the process is automated end-to-end, including disaster recovery. I have several ESX4i servers and plenty of storage space available to them over SCP. My current Internet connection gives me enough bandwidth to be more than each customer's WAN upload speed (I can accommodate several of them at the same time actually).

My question is this:

What would be the best Acronis option to provide nightly backups (incrementals in a GFS plan most likely) to a central vault at my office, and (ideally) to their local NAS?

The solution would work if I store Acronis backups (TIB files) but would be even better if I can store/generate VMs for the clients at my office, because then I just have to bring a spare ESX4i to the client and they are up and running.

I've read about vmProtect6 and that product might do the trick but I can't find any whitepaper on how to deploy it in such a scenario.

Any help and/or pointers to white papers would be greatly appreciated. I'm sure I'm not the first one who wants to offer such a service to their clients.

A consultant friend of mine actually does this same thing using ShadowProtect products and it works quite well. Being an Acronis guy I'd like to see if Acronis has the products and technologies to do this also.

Thanks,
Christian