My friend and her partner opted to go with a known donor to have their daughter. My friend was the birthing mother and her partners brother was the donor. Their little girl is now one and they are happy with the donor playing as much of a role as he wants to. They all live in the same town and he is married with 3 children to his wife. He regularly see's his 'donor daughter' (term my friend uses) at family events etc and is happy to let her mums make all decisions regarding care etc as he see's them as her parents and himself as more the uncle.

Mind you I have to point out this is very much a situation based on great trust and a very close supportive family. It is not one carved in stone and will obviously change as the little girl gets older. I can only suggest that if you go with a known donor have clear ideas and understandings set out before you go ahead with it.

Good luck I hope you are able to work out a parenting situation that works for all of you.