I just thought of Ysolda in Whiterun. Her quest required to gain favor with her is just to bring her a mammoth tusk she can trade to the Kahjiit caravans. You can buy or find one of those and bring it to her as a "dower". She has her own home which you can move into after marriage, but apparently she won't go into business for herself unless she's living in a player-owned house.
She'll ask you where to live. If you move in with her, she opens a shop. At least, it worked for me.
Ah! Maybe that was what I remembered reading somewhere.