While I have no information to share about how to become a HD dealer, I can say that independent shops can do OK for themselves, if, they do a good job (you only get one chance in this department), and you keep your expenses at a minimum. Where a lot of guys go wrong, is in the initial capital outlay. Once you put that cash upfront, you have to constantly have work just to make your mortgage payments.
There is a guy near me, who works out of his garage. Only does one or two bikes at a time. While he is qualified enough to do engine rebuilds, the majority of his work is tires, oil changes, tune ups, and other repairs. He works on a cash only basis, and my friend who introduced me to this guy, told me he's doing about $75k a year. There are always people bringing their machines to him. He is very knowledgable, and reasonably priced. You can expect to wait up to two weeks for an appointment.
It can be done, you just need to start small, do a great job, and keep the expenses down....