Can Tesla do something like pick a dealership and add conditions like, "must sell only tesla or only electric cars", "Tesla will retain the right to sell directly too" etc? Why are the standard auto makers not able to sell directly? Is it because A: the law stops them or B: They had signed exclusive agreements already. If Tesla starts with a clean slate, can it have dealerships and sell directly too? Or at least have some more balanced rights and decent negotiating position compared to the gas giants who are wimps against NADA.
Yes, Tesla could do all of that. Most dealers wouldn't sign such an agreement. For that matter, most dealers wouldn't want to sell an electric car.
Seriously, most existing car dealers don't know how to sell an electric car and make money at it. Since, for the most part, a Tesla requires far less maintenance than a modern internal combustion car, and since, for the most part, the biggest profit center in most car dealerships is the service center I can't see how the existing dealer networks can adapt to selling a Tesla or any other electric car.
Right now there is a dizzying patchwork of laws requiring automobiles be sold through dealers and not direct from the manufacturer. Historically, a lot of this was to protect local small businessmen (car dealers, who even today are quite well represented in local government). The other argument was that with a local dealer the purchaser of a car could also be sure his car could be serviced locally as well -- and since an electric car requires so much less service, that logic is kind of questionable.
Oh, and car dealerships (or any franchisee) can protect themselves from being undercut by the automaker by insisting on the same terms as any other dealer in their territory. There is also this thing called the Sherman Anti-Trust act that also prohibits undercutting your own dealers.