Jon,
Are you in luck. Michigan tap water seems to be very good for ray breeding. I know of at least eight people in michigan that have bred rays.
Right now, your best chance is Pat at Amazonstingrays.com. He is a community sponsor here. He breeds some very nice motoros and he sells some wild caught ones as well.
He is actually in Troy. I am sure that if you contacted him he would be more than happy to give you a tour of his ray room and let you pick out a fish.
Colin