You could try to find a retailer who would be willing to deal with the hassle of placing an order for you.
Typically wholesalers only deal with large quantity orders with minimal drama involved. They don't have the ability to deal with individuals who only want a few trees (or even 10 or 20). I have purchased large quantities of stock from some growers in the past (200 or more trees at a time) so it can be done with the right nurseries. You just have to find the right wholesaler and make it worth their time (and get lucky). You will have better luck with growers who deal with seedlings and smaller clients than the big commercial wholesalers that deal with larger retail customers and larger stock. On one end of the spectrum you might have a small grower of black pines in Oregon for landscaping, on the other end you might have someone like Iseli who deals with specimen trees for large retail chains. You stand a better chance with the former and ZERO chance with the later.