In the wake of a major service outage a few weeks ago, fourth place US carrier T-Mobile may be shopping around for investment money from another US cell provider. Compared to the other US carriers, T-Mobile has a very small 3G footprint. Recognizing a need to expand, rumors indicate that parent company Deutsche Telekom is courting the likes of MetroPCS, Clearwire, and even AT&T.

Any of these investors would receive a small stake in T-Mobile in exchange for investment to expand their network. MetroPCS is of particular interest as the smaller carrier uses the same odd 1700Mhz 3G frequency that T-Mobile does. Collaboration with AT&T would be risky due to possible anti-trust allegations. AT&T is the only other GSM carrier in the US.

Deutsche Telekom’s T-Mobile UK was recently forced to merge with Orange UK. Could their US arm be headed in the same direction?