I could theoretically get to the 6'3"-6'4" range if I wore gigantic elevator shoes with platforms on the bottom, but it would be really obvious and it would be hard to walk and my feet would get sore. I think I'll just get ones that make me almost 6'2", and then claim to be 6'1", since the average shoe adds about an inch, so if I'm 6'2" in elevator shoes, I can convince people that I am 6'1" barefoot.
The trick is to wear long pants so that the raised part of the shoe that accommodates the lift is covered up...otherwise it's too obvious...and practice walking in them so you don't walk unnaturally.