We spoke about this the other evening when you were here, but I've heard negative things about breeding too close for a long time. While I agree, you can't do it generation after generation I've personally witnessed three litters of brother-sister, mother-father crosses that made exceptional dogs. I tend to believe more of what my eyes see, than of what my ears hear.
You are right Bryant, your eyes will tell ya ha ha ...it can be done with success and carried on for a good long time with culling and selection.