Portman 20.0
Rubio 12.9
Christie 11.0
McDonnell 7.2
Ryan 5.5
Daniels 5.2
Rice 3.5
Thune 3.4
Martinez 2.9
Ayotte 2.8
Jindal 2.8
Bush 2.7
Pawlenty 2.5
Rand Paul 2.0
Santorum 1.9
Pawlenty should be tied with Portman.
2 months later:
And Pawlenty is surging like mad, now up to second place.
----
GOP VP nominee
Portman 25.0
Pawlenty 17.5
Rubio 15.1
Christie 7.4
Jindal 5.9
Ryan 5.5
Thune 4.3
McDonnell 3.0
McMorris-Rodgers 2.0
Rand Paul 2.0
Rice 1.5
J. Bush 1.4
Ayotte 1.3
Daniels 1.2
Huckabee 1.0
Martinez 1.0
But I haven't found a way to play having only American credit cards.