In reply to Frank R.:
We'd love to do one too!
But the seasonal concern would be magnified even more in this case, as you rightly point out. It was hard enough guaranteeing sufficient suitable winter use for the B1/B2s. I shudder to imagine ourselves halfway through a B3 bumper test right now, with the winter we're currently not having.
I'll never say never, but I suspect the logistical/seasonal hurdles, and the sheer breadth of the offering, would always count against a B3 group test of any scale.
Perhaps we all need to move to Norway