Hopefully Total Wireless will offer 4G LTE within the next month or two... all the other America Movil owned MVNO's that use Verizon towers such as Page Plus, Straight Talk and even Tracfone already offer LTE.
Selectel, a Verizon MVNO not owned by America Movil, will start offering 4G LTE next week.. and they have roaming off Verizon tower at no extra cost (if what I read on Howardforums is accurate).