I think it highly unlikely that SKW (or any other sane regional) would buy Midwest or any other independent airline. The regionals have a relatively lucrative deal providing codeshare feed, and would be VERY foolish to throw that away by conducting ill-advised independent operations. Any such operatio would eventually compete with a code-share partner...at which point the gravy train would end instantly

The only way to run an indepent op and NOT compete with your codeshares would be to severely limit the scope of such an operation...what would be the business sense in having a limited operation with no growth potential?
There are no rumors to this effect, but purchasing Mesa MIGHT theoretically be an attractive idea:
1) Labor is treated so poorly that SKW could simply bring them up to SKW standards and they would be eternally grateful.
2) The sketchy mesa codeshares could likely be solidified simply by confidence in a responsible management team.
3) Mesa could probably be obtained for less than it's potential value.