I would recommend Early Classic Enterprises (
ECE). They offer some of the best products and customer service that is next to none.
I haven't personally ordered from CPP but if you check out the review section of the board several board members have ran into difficulties with them.
Also... depending on the brake setup you want to run, you could technically run a manual disc-drum (if wanting to save money) and still run 20's. And, depending on the wheels you choose you might even be able to stick with the 6-lug setup.
Just my $.02... (again)