Actually, it's more likely to see T-Mobile and Dish partner or even merge. T-Mobil's financials are not that great and it is struggling with its small market share, and they need spectrum; Dish needs to either partner (both Charlie and Joe have said this clearly) with a carrier or otherwise gain such assets (Joe has dangled the possibility of buying more companies if it fits right). Just as Charter Commnications and TimeWarner Cable have said they are now primarily ISP's, and the video business is just an additional offering, Dish won't just be a DBS company anymore, but is seeking to be (along with Google, Verizon--FiOS so yesterday
--and Sony, and other companies I can't recall) to be an internet (or IPTV) video provider ("If I were building Dish Network today, I would not be investing in satellites." -Charles Ergan) with Dish also offering wireless services. T-Mobile and Dish is the match made in heaven, not AT&T and Dish.
AT&T may offer to buy Dish's spectrum (I believe Dish owns the spectrum, NOT Echostar), but they don't want a huge DBS company with its problems (that Joe Clayton is trying to fix) and redundancies to its own TV service using technology (DBS sats) that while more efficient, are far more expensive to operate than an OTT service or such via internet, considering Dish itself is moving away from DBS and its higher costs. Heck, I read where Verizon, as a consequence of slowing FiOS build out even more, are now trying to work with cable cos. to offer Verizon TV packages as an alternative to cable cos. high costs to provide the TV service they do now!
T-Mobile and Dish need each other, badly. We'll have to see how it all plays out.