I've built several '51 Tele 5's the past few years, and include several variations of this design in my offerings list. as visual reference to my thoughts below, here's one I built for stflbn earlier this year
given the experience I have with designing/building these, I'd offer these thoughts on your 6'er ...
- biggest issue will be getting a 6 in-line headstock with cloverleaf tuners to aesthetically and functionally work. a 5-string in-line headstock is really pushing the 'length out there' envelope IMO, and a six could have string length issues leaving you to purchase a single extra long string for the high string to accommodate the standard length of the low string and still have its wraps hit the tuner correctly
- finding a bent plate styled bridge could be tricky, but I'm sure you could work with Hipshot to have a custom bridge made if you didn't make one yourself
- you're going to need to have a custom SCPB pickup designed and wound. there are several companies that can help you with making one of these. I know, as all of my 5-string SCPB's are custom wound for me
all the best on your project,
R