I could do it. I think one of the criteria to be a surrogate is to have finished with your own family (ie. finished having your own children or not planning on having any of your own).

I also think that most, if not all, factors to consider, could be dealt with lots of communication between the parties. Other children will understand that Mummy is having a baby for someone else if it's explained to them and their questions are answered. I don't think that part would be difficult tbh. There's a lady who wrote a book recently (I think she lives in the ACT, not sure) and she was a surrogate for someone. Her main concerns were the legal ramifications, because surrogacy law is not particularly clear-cut in each State. For example, she says that if it turned out that the baby she was carrying had a disability or genetic abnormality, and the biological parents decided they didn't want that baby anymore, the surrogate would be expected to parent the child or put it up for adoption if she didn't want to.

I think surrogacy, or egg/sperm/embryo donation is a wonderful thing, if it goes well. I expect in most cases, and where the law is clear in protecting everyone involved, it goes really well. And what a wonderful gift to give.