Since I posted a somewhat snarky comment (that I stand by -- I am pretty fed up with people telling me that plainly possible things are impossible), let me at least say how I feel about the issue.
I don't see any compelling reasons for MO rep to be transferred over to this site. For once I completely buy the standard SE explanation: it doesn't make sense for reputation on one expert site to carry over to another expert site, even one which is closely related. Just because a user has a great ability and proven history of answering questions about Area X, it does not follow that they have the same ability in Area Y, even if Area Y is at a "lower level" than Area X. (It may well be true in many cases, but if so, this will become evident via the normal channels of site use.)
To veer into the personal, I am currently preparing a tenure dossier and my teaching has been evaluated at all levels. The average departmental teaching scores are an increasing function of the course level: i.e., lowest for calculus, highest for graduate courses. This is true for my own evaluations as well, but with a much higher slope: my teaching in terminal, one semester freshman calculus is visibly below average and my teaching in graduate courses is visibly above the (high) departmental averages.
I have been among the top three highest rep users on MO for the last several months. (Amusingly, this made it into my tenure dossier as well, a sign of the success of MO.) I do not aspire to be, and probably could not be, one of the highest rep users on the proposed calculus.SE site.
I do think that ideally someone who had a good rep on MO should get the same privileges here that established users on the SE2.0 sites get: to that extent, rep should transfer over. On the other hand, I don't completely approve of the idea that someone with some SE rep gets an automatic 101 rep when they log into this site. On the earliest days of the public beta, 101 rep was enough to put these users above most of the people coming over from MO, who could not immediately vote, make comments, etc. In my opinion a better solution than "complimentary rep" is "complimentary abilities": i.e., allow someone who is a documented serious user on another SE site be able to vote and make comments as though they had the small amount of reputation that was necessary for this.