I think the backspacing you're looking for is way too much. 5-5.25 BS will tuck the wheels way into the wells and, if you are running a wider tire, may cause rubbing. In fact, the 4.5 with wider tire may be too much. If you can gat a 3.75 or 3.5 BS, I think that would be ideal. Not to mention the wider stance will look and feel better.

I don't think you'll find a wheel with the BS you're looking for unless you have them made...

Good Luck (from the guy who is too poor to afford a Gen 3)!

Edit: Apparently I'm talking out of my butt. After re-reading the above posts, it looks like the wider tires will fit your rig with factory BS. I guess I don't get it. Anyway, the biggest BS I've ever seen on the Steelies is 4.5. My guess is to go with those if you really like the look.