I think Vespa has some pretty lofty requirements for their dealers. Japanese scooters are out, at least new ones. To become a Japanese dealer, you have to carry their whole line, which includes motorcycles, ATVs, personal watercraft, etc. and you must meet certain quotas. I agree about staying away from Chinese crap, it will ruin your reputation quick. But there are still several "scooter only" brands left. SYM, Kymco, Genuine, Adley, Lambretta, Aprilia also allows dealers to only carry their scooters, without having to deal with high dollar sportbikes. The Lance Cali Classic also seems to be popular around here, and also seems reliable. Lance used to be Chinese, but I understand the Cali Classic is built by SYM. Kymco alone has a scooter that would suit just about everybody, from 50cc to 500cc. They seem to be the most dealer friendly and customer friendly scooter company around.
I could not afford to open a dealership, I don't have the capital. There is a ton of expenses up front. You have to acquire a building, make all the necessary repairs and modifications, it has to pass city inspection for a commercial building, You need all kinds of expensive permits, You need utilities, you will need to have insurance to cover the building and all it's contents, including the scooters, tools and equipment, parts and accessories, etc. Because you will be working on motor vehicles, which involve gasoline, there are special requirements and insurance will be higher. You will need an alarm system and a company to monitor it. If you have employees, you will have to pay benefits and unemployment insurance in addition to their salary. I would start out with a part time mechanic and see where things go. Scooters come in crates and have to be assembled, which should be part of your overhead. Once you become known as a "fee" dealer your reputation is ruined. You will need to set up a connection with the department of motor vehicles so you can put plates on scooters and do the title work. You will probably need the services of an accountant. You will need to pay for your tools, parts, and scooter inventory up front. And on top of all that, at least in the beginning, you will need some form of advertising to et people know you exist, and you will need a decent web site, and..........