We're having the same issue here in Seattle with our Fox affiliate, KCPQ. Both KCPQ and KTXL are owned by Tribune Co. and, at least in Seattle, the issue is that Tribune wants Dish to carry not only KCPQ-HD, but another station they own here, KMYQ (part of MyNetwork - the one that came about from all the leftover stations when WB and UPN became The CW). Dish, (rightfully in my opinion) doesn't want to carry KMYQ in HD b/c, well, there nothing there that anyone wants to watch and it's a waste of bandwidth (again IMHO). But Tribune is holding out and won't let Dish have HD rights to *any* of their stations until they agree to carry *all* of them. It's a crappy situation and has been going on for just about 2 years (since Dish lit up the other three local networks in HD).
Check out other threads here about Q13 Fox and locals in Seattle for more info. The only ray of hope we've had over the last year is that, supposedly, the general carriage agreement b/t KCPQ and Dish expires sometime this summer so they'll have to renegotiate a new one. And you can believe that KCPQ will do their darndest to get Dish to carry them in HD; I don't think Tribune would want to face the possibility of not carrying Fox at all in Seattle (Seahawks are on that channel) so hopefully when/if they have to renegotiate, we'll get HD. And, then, maybe, KTXL will, too.