T-Mobile has no announced partnership with Google PERIOD. Sprint has no announced partnership with Google PERIOD. AT&T has no announced parnership with Google PERIOD. Verizon does.
From what I can see, T-Mobile has gotten THREE new Android phones since August: the MyTouch 3G, Samsung Behold 2, and the Motorola Cliq. Sprint has gotten the Hero and more recently the Samsung Moment which is no low end phone at 800MHz with an AMOLED display and qwerty slider. It's not like either of these two are behind Verizon by any means. They chose their hardware releases. I don't see why they'd get anything ahead of Verizon. AT&T won't be getting anything high end any time soon not made by Apple. I doubt they were permitted to negotiate anything before the contract was up which means in another week, they can start thinking about other smartphones, but that won't mean getting something anytime soon. As far as I can tell, Verizon is in the driver's seat.