This claim is almost a slip of the veil.
Newt is a the establishment RINO candidate that is branded to be more appealing to true conservatives.
It is all marketing/ spin.
But, if Cain asked him to be his VP, would he accept?
Full disclosure, Cain is #1 and Newt is #2. You can not conclude that Newt is the establishment candidate just because he was in Washington for many years. Example, Newt pissed the RINOs when he fought against the Bush I tax increase (Read my lips, no new taxes (for 2 years)). He also ticked off the insiders when he instituted term limits for committee chairs (he passed this when he could not get term limits passed). It was the insiders who ran Newt out of town in 98. They could not wait to get Denny Haster in and start earmarking.
Newt is proposing many things in his contract which will piss of the insiders. The insiders will figure out Romney is only a 23% and turn to Newt. My concern is that they will the asked him to tone down in new contract to become the "acceptable to everyone" candidate and he will oblige .