@engineer,
I pretty much agree with this.
The consensus on the top possibilities are: Pawlenty, Portman, Rubio, Jindal, and Ryan, with Susannah Martinez thrown in every now and then for fun.
The first two are boring but won't scare off independents. Rubio is more exciting - and would help in FL - but has waned recently in popular prognostication of the pick. Jindal and Ryan would excite the Conservative base, but neither would bring a state with them and neither would sit comfortably with many independents.
A Ryan pick, in particular, would inextricably tie Romney to Ryan's plan that guts Medicare and SS to cut taxes for the rich. It's hard to see how the WH isn't salivating over the chance to run against that.
Cheers
Cycloptichorn