Honestly ... I've be a little worried that a rogue Paul supporter would try to assassinate Mitt if it were the other way around, face it - there are weirdy's among us.
There is no need for assassinations anymore, unless it was really the only thing left they could do. We live in a different time now. The media is nothing like it used to be. 50 years ago ya had, what, 3 channels of news? No 24-7 corporate spin machines of vile propaganda herding the sheep, no internet, etc. All of that now can be used to spread lies/rumors and bring a candidate down just as easy. They have way easier methods and tactics today. Back then, they really didn't, so if something had to be done, they just got rid of you.
Ever notice how it was always some loser who no one has ever heard of too? Always some patsy type nobody

The evidence behind LHO killing JFK is overwhelming, there is no doubt that he did it, but he was listed as what's called a 'Domestic CIA Contact' and was followed around constantly even during his days in Soviet Russia. His 'buddies' he had ties to as well in New Orleans had big mafia/fbi/cia ties as well. RFK's 'killer' also never really killed him either, it was reported by cops afterward there were shots fired behind him before he got to RFK, so he was basically used as a diversion to pin it on. Same with MLK's killer, the attempt on Reagan, etc. It's always some 'disenfranchised' loser type they dig up, an obvious pattern.
About Reagan too that some mentioned with Bush, i remember Paul C Roberts (served under Reagan as Treasury Secretary Deputy) said that Ron would have a hard time like Reagan as president. He said that Reagan really only got in because of Bush and his henchman, and they said that if you don't allow Bush and others to join up with you, we won't support you, and they did this same thing with Goldwater/Rockefeller. It is possible that Barry could have gone a lot further and not got obliterated by Johnson if had rubbed elbows a bit. You can see the correlation with Ron here, as with Goldwater, he distances himself a bit too far from the neocon base. I dont blame him for this, but it can tend to backfire, and this is something Rand plays a lot better. Bush pretty much called the shots during Reagan's time, no different than Cheney under GWB. They all knew GWB was a complete space cadet, and since Daddy Bush and Cheney worked together at the start of the NWO going into 5th gear, well who better to have behind his brain dead son pulling the strings?
I just don't think a PAUL/ROMNEY ticket would work though, the contrast is just way too far apart. And the other way around would be completely useless. I would much rather just have Obama back, and then Rand can run in 2016, if the country (or even the world) still exists.