8 lug rims are one of the most easily available rims you can get.... Best of all, they are available in 16 inch which opens the door to tons of tire sizes...
For the money you want to spend doing this, you could go to a junkyard and pickup some nice 8 lug aluminum rims that would really spice up the truck....
And, if you ever need rear-end axle choices, the corporate 14 GM rear end is super common (put in trucks up through 99 or so), comes with MASSIVE drum brakes, and can have axle ratios from the low 3's all the way up to 5.17 and beyond..... Lockers, posi's, you name it.
I say leave it 8 lug.
