I just built one of the KRANK Long drive drivers in 6* and at 47 1/2". Not had a chance to play it yet as this is the dead of winter up here.
This thread gave me a bit of confidence though, so I am very excited to try it ASAP.
It's mounted on a Fujikura Flywire X, which would normally be too stiff for me, but as it is 2 1/2" longer, this should turn out great. Thanks for the thread.