Some folks do run 10" on back, most with at least 4.5" backspacing and 1" relocated springs using the Dr. Diff kit. I ran 10" rims on my Roadrunner, but the airshocks kept the tire sidewall clear of the fender lip or it would rub. Tire height is also going to matter, if the tire diameter is small enough you might clear the fender, but not sure how that would look.
Later, Jim