Maybe I'll try my big white roo over my best black pullet to see if I'll get any barred birds!
My lines were pure, so it's entirely possible that it is lurking there in the genes!
As for the blue discussion, this has been my experience:
Black x blue- I've noticed this results in the more evenly colored birds. The birds overall have a darker blue appearance and the lacing doesn't quite stand out like I would like. If you use this breeding, be prepared to use a blue x blue to lighten the main color of the feathers.
Blue x Blue- This can be hit or miss. The feather color will be even, but it could be a darker blue or a lighter blue. The lacing tends to wash out with these, so if you are having an issue with lacing, breed to a black bird to get a darker lacing.
Black x Splash- This has produced the best for me thus far. The black for some reason really seems to help darken the main feather color and the splash keeps it light enough that it's not too dark. The lacing is fantastic so far.
Blue x Splash- I have not done this cross as of yet, but am hoping to later on down the road.
Splash x Splash- This will not produce blue. As you breed, from what I have heard, the splash color gets lighter and lighter. There will be more and more white on the birds. I don't know how this will affect the splash x black breeding
Now, as to the black coming from a blue x blue or black x blue breeding, I haven't found anything to support this yet. Overall, the feather width is not as wide as the feathers on a black bird. Supposedly, the feather quality is not the same either. Blue feathers do not "stick" together as well as black feathers. They look frayed instead of nice and smooth. This could transfer to your blacks should you use these blacks from a blue breeding into your other stock.