Can Ford not put vehicles in public areas with associated literature (paper marketing, iPad kiosks, etc), and take orders from that mobile device or via a customer's phone?
The order takes place where the servers are (the same as when you buy a Model S on teslamotors.com), and you would be prohibiting the corporation's freedom of speech (finally! a use for Citizens United that sucks less) by preventing them from putting a vehicle out in public (if they have approval of whomever owns/controls the underlying space).
Citizen United was about political speech, not selling cars. There's a long history of the court taking differing approaches to commercial speech vs political speech. Ford most likely could open up stores to distribute political literature. They could even likely make a Ford movie. What they can't do is sell cars.
The court generally errs on the side of the people when it comes to political speech and on the side of the state when it comes to commercial speech. I don't see Ford having much of a case opening up dealerships under Citizens United.
The other model that some legacy manufacturers are working on is to let customers go through the whole purchase process on their corporate web site and then just take delivery through the local dealer. The dealers are happy with this arrangement since they still get to profit on the sale and don't have to do any sales work.
"Motor vehicle dealership" is a term defined in c. 93B as: "any person who, in the ordinary course of its business, is engaged in the business of selling new motor vehicles to consumers or other end users pursuant to a franchise agreement and who has obtained a class 1 license pursuant to the provisions of [G. L. c. 140, §§ 58 & 59]"
Because neither Tesla nor Tesla MA is engaged in the business of selling new Tesla motor vehicles in Massachusetts "pursuant to a franchise agreement," there appears to be a question whether Tesla's business model involves the operation of a "motor vehicle dealership" ... and therefore whether, by its literal terms, the proscription of § 4 (c) (10) applies to the defendants at all.
I suppose that if Ford set up "showrooms" in the Natick Mall and tried to claim they weren't "franchises", the Court would consider reading the definition more broadly, but I'd rather any Court read statutes as being as minimally intrusive as possible: No franchise agreement? No problem.