I think a lot of us have dogs with irregular nipples. Some close together, missing one etc, here was a therad about it a while ago. I shouldn't worry about it.
However i'd say that it's suchhhh a bad time to think about breeding your dog what with the credit crunch and there being so many dogs in rescue because of it; there are lots of litters of pups that can't be sold.
Various other reasons too but really, there are just not the homes for pups at the moment unfortunatly.