You could always run the 8 lug dually rims. Swap in a 3/4 ton running gear and run the dually rims on that. Or just change the spindles from 6 lug to 8 lug like this guy did
http://coloradok5.com/8lugconversion.shtml
I love dually blazers, planning on building one in the future, and think even a pseudo dually would be cool looking. If you can't get the photoshop guys on here to do you up a drawing drop me a message and I will mess around and see what I can do for ya.