I'm 6-9 and picked up some Deegan FMX bars made my 909 (same thing as Pro-Taper). The Deegans are 4.9 tall, while Pastrana's are 4.75. I needed every bit. Also have adapters which add 3/4 inch. My cables really are about at the limits, but there were no modifications to them.
Combined with a 1 inch taller rise in the seat and this bike ROCKS.. I hate riding everything else and none of my friends can kickstart mine :) (doesn't help having 250psi compression)
I should also note that I physically couldn't stand up on the pegs while riding before. Was just way too bent over. At least now I can stand, but it's uncomfortable. I don't care though, I wanna ride.
Micah
P.S. Contact 909 Direct for the bars. I think they are being discontinued at DennisKirk/Rocky Mtn., but they should have new ones still direct.