6.70-15 works out to a 215/75/15 in a modern size. A wheel to consider if you want a wider tire would be the old Blazer Ralley, 15 x 8. That size and application is available in aftermarket wheels, too, just make sure to specify a Blazer 4x4 application and then order the centercaps separately (the caps that come with them will have holes in the fronts for the 4x4 hubs). You'll also want to specify an 8" width, 7" will be a Japanese truck fitment with the wrong backspace, and will rub.
I'm running the Blazer Ralley (there's a pic of them on my signature link) with a 30x9.50x15 tire, lots of clearance with no rubbing. It's not bad to steer, but I'm a bit of gorilla, so it doesn't bother me.
