I wouldn't call them unstoppable, although they would be very formidable.
It may be time for a female VP, and if there is to be a female VP, then why not Senator Hutchison? She fits the bill just fine.
On the other hand, two Senators haven't been too successful of late.
In that sense, perhaps McCain/Allen or McCain/Romney would be the right way to go. I realize Allen is a Senator, but at least he is a former Governor as well.
Another ticket I like with McCain would be John McCain/MarkSanford.
I picked the McCain/Romney ticket and the McCain/Sanford ticket in 2005 and I stand by them.
I still like both of these tickets in 2008.
McCain/Allen is no longer viable at all.
If Senator John Warner of Virginia was 20 years younger, I would say that McCain/Warner would be a great ticket.