Clearwire LTE is going to go on existing Wimax towers and be deployed in areas where sprint or other companies need them to be in. Most clearwire sites are apparently having upgrades on their backhaul which is resulting in much higher wimax speeds these days. So basically, if you're in an area with preexisting wimax coverage then you'll most likely get some sort of clearwire TDLTE coverage in the future.
800mhz goes on every tower. They just need to hook it up to existing RUU's. If you look at the pictures around here, you'll see that they already have the 800mhz "plugs" on the panels but they're not connected yet.