^We have two HDTVs both connected via wireless.
For UVerse programming and recording you'd never know it wasn't hardwired. I'm guessing they did some network tweaks and optimizations with the Ciscos they provide. And I'm sure they give their own services top packet priority on their network. The DVR is handled by the main box AFAICT. So regardless of where you told it to record from, it streams it anywhere. Never had a hiccup. Yet.
As far as compression goes, that's one approach. But there's other tricks you could use such as intelligent preemptive caching, QoS tweaks, and buffering too. But don't expect AT&T to tell you much about how they do it. That's their little competitive secret.
And yes, it will always break after a point. Which is why they only support three or four (I forget) wifi TV routers per account. So figure 4 TVs max. There doesn't seem to be a published threshold for wired however. But that would likely be whatever your network topology would allow on 1GB Ethernet. I never tested it, but inbound seems to run near T1 speed on the WAN end.
