Nobody will merge with US Airways. It's a poorly run and poorly managed airline and while they may be doing "OK" right now, they're struggling to keep passengers and improve customer satisfaction. Not to mention that they usually have higher ticket prices and they charge for a lot for things (bags, food, drinks, etc.). US Airways tried to merge with United at least twice, getting close in 2000 where they stopped short of announcing the merger and they tried to merge with Delta in January, 2008. I don't think American is in the merger "mood" (that's a BIG airline, so they buy other ones such as TWA).
The United-Continental merger will certainly be interesting however I think that they will make some good decisions. Management at Continental is better than United and both airlines are pretty strong right now. Obviously having 10 hugs across the US will not last and some will likely lose their hub status and I think Cleveland will likely be one of them at some point. It will certainly be interesting to see how things play out over the next year or two.