This was a huge plus for planning a home birth for me. We don't live near family either and my son isn't keen on going to other people. I do have an aunty & her 2 early-teens sons about 45mins away who we will call to play with our son if he's not coping at the birth but I'm guessing even if we do need someone else it'll only be for a couple of hoursof the intense part and the rest we're just home anyway.
I think sharing birth with children is a wonderful thing but I personally would be hesitant to take them along to a hospital birth as they are stuck in a strange room with you and it may be uncomfortable for them.