LOL, yes he would. It is very unlikely Romney would chose Santorum, but if he did Rick would not likely pass up a once in a lifetime opportunity like that. That is not a criticism of Rick, it's just political reality. Palin knew what McCain was, but she ran with him anyway. Bush Sr. ran a very contentious campaign against Reagan, yet he did not pass up the opportunity to be the VP candidate. If Santorum believed he was an easy front runner for 2016 or 2020 then I could maybe see him declining such an offer. Unfortunately for Rick, the Republican bench has some very strong future contenders and there is no reason to believe Santorum would be especially strong in any upcoming election cycle. I very seriously doubt he'd reject a chance to run as Romney's VP if he were asked.
But you can be assured whatever Rick does it will be to enhance his political aspirations. It's how he works the field he plays in.