I have the same 3" extension kit as 4trax has. Is a lot better with my 6'7" compared to stock. Still 4" or 5" might even work better for me.
I noticed that being able to stretch te legs more increased comfort incredible.
Some of my less taller friends experience the same as I did.

http://www.fatbob-bikers.com/apps/ph...toid=101217037

http://www.fatbob-bikers.com/apps/fo...s/show/4752762

 

'08 fatbob here. i have the same problem trying to get my feet comfortable at speed. i wind up putting my feet on their outer edges . problem is my legs are bent sideways and after a couple of hours i get bad pains in my knees and hip joints. i put mid control foot pegs on and they feel much better at speed.since i do very little in town type riding , i wish i could have gotten the bike with mid controls and then installed forward pegs for the change of position.

 

So change them. You shouldn't have a problem selling (or trading) the forwards for some mids. Then pick up some highway pegs.

 

I had to switch to forwards because of my knee's. But then I also adapted the floor boards. Love them! But at highway speeds there is some floating depending on where you put your feet!

 

Why? Because everyone is different. Some like blondes, some brunettes, and some read heads.

 

And some like em ALL!

 

Had the same issue as OP. Got a pair of Kuryakyn Liberator pegs with stirrups, made a huge difference.