We’re working on a project to expand the single cloud - single hub DMVPN to a dual hub - dual cloud DMVPN. This will provide us with some fault tolerance in the event of a hub failure.
We are also planning the use of VRF-Lite in order to carry some other networks, including commercial Internet, to our remote sites. With a little luck (and some documentation) this should keep the security Nazis happy.
Shared IPsec with DMVPN and VRF-Lite http://www.networking-forum.com/blog/?p=1110
Intro to VRF lite http://packetlife.net/blog/2009/apr/30/intro-vrf-lite/
Using VRF-Lite, EIGRP, and Static Routes http://www.netcraftsmen.net/component/content/article/68-network-infrastructure/681-using-vrf-lite-eigrp-and-static-routes.html