I soon hope to be in the same boat. Was/am union electrician still paying my dues every month but I own a single man shop at the moment. My business is residential service and when I need to hire I really want to hire union. I believe that some of the apprentices who worked under me at my last job when I was a GF would be willing to work for me now. But the company we worked for did some commercial service so guys had vans and are somewhat used to service calls. I believe with my service rates I'll be able to pay good service guys gf rates and more. All that to say I think you are looking for shop rockets who don't want to travel and don't mind doing residential. You pay enough and I don't think they will mind. But you are going to have to train them. I was that guy I am describing and I would have never started my own shop if our shop wasn't so cheap in how they ran things.
I'm glad to see another electrician striking out on his own. A couple of things struck me about your reply that perhaps you are not aware of.
"I really want to hire union" - Since you are a union member, you really have no choice. If the hall finds out you are running a nonunion shop, you will be brought up on charges. Expect to sign an agreement with the hall and do all your hiring through them. The only time you can hire outside is when they cannot supply workers. Then you can hire outside, but you must have these workers sign up with the union.
"some of the apprentices...would be willing to work for me now" - Keep in mind that apprentices are not allowed to work without supervision so you can't put them on a service truck by themselves. Also the apprenticeship school probably has a policy of rotating apprentices to various businesses so you won't be able to keep them long enough to justify a lot of additional training expenses.
"did some commercial service so guys had vans and are somewhat used to service calls" - Commercial businesses are more lenient with service electricians who are rough around the edges. If you are planning to do residential work, many of these guys will not fit the bill. (See my list of resi service electrician requirements above.)
Keep in mind also that it is difficult to hire workers if you don't already have a full schedule of work to keep them busy. Going from a one man shop to a two man shop is very hard. You need to be scheduled out at least two weeks constantly to justify the cost.