There's reason to be optimistic. Fox is giving the most expensive (and critical) part of what's needed to the affiliates (and installing it themselves). And Sinclair has announced some major equipment purchases. But even without Sinclair's contribution, they could still show all of the network HD and switch back to SD for local commercials and non-network programming. So, bottom line, I'd bet that they'll show all of the Fox net's HD programming when it starts in September.
Now, boosting signal strength to something more than 24kw would be welcome... No telling when that'll happen, though.
-Reagan