Reuters has a story about T-Mobile US parent company Deutsche Telekom seeking a partner for its US T-Mobile network. Reuters article: Deutsche Telekom seeks partner in U.S. - report | Deals | Mergers & Acquisitions | Reuters An related note, I think the general public doesn't know that Verizon Wireless is a joint venture with a non-US based company; Vodafone. See this article: Vodafone CEO: Need To Resolve Verizon Wireless Situation It isn't mentioned in the article, but I think Vodafone owns 45% of Verizon Wireless.
If the deal did include a stake in Tmobile, that might exclude AT&T or Clearwire (due to their close association with Sprint).
Kind of... AT&T's 3G network and T-mobile's 3G network run on different frequencies which requires different hardware.
Both companies (AT&T and T-Mobile) have licenses to AWS 1700 band, so it's just a matter of time before devices come standard with AWS and PCS 1900 bands just like they do now for 850 and 1900 bands. That will not be an issue in the near future as devices will soon be available to operate 3G on both bands.