If you're looking at buying "staggered" wheels, I'd advise against it. If you're dead set on getting something like that, you're going to have to find a tire that fits BOTH widths of wheel properly. Not a huge deal, but something to consider.
I don't know how it would work out when it comes time to rotate your tires, either. That's something else that might be an issue. Or just never rotate them?
7" wide in front and 8" in rear might look okay, but rotating them so that the 8's are in front might wind up looking a bit off.