I've got a similar problem,I'm 6'4".
This has been discussed before in another thread.

I'll be waiting 'til i've fully bled the system,and driven it before I decide whether to cut down the arm.
I've only got the brake as mine is now an auto.
My dual M/C has less travel than the original so I don't see a huge problem in cutting it down as long as the pedal doesn't bottom out on the floor.
I would cut the pad off,then remove the desired amount and make sure your welding's good!

1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.