Try the photo galelries on this site, user vehicle pages over on FXN, or cardomain pages.
Here's a couple shots of mine. I have AT Italia Presa wheels that I got from TireRack. They are 18 x 8 1/2, with a +38mm offset which keeps them inside the fenders. I am running 275/55/18 Michelin CrossTerrain tires, which are a little bigger in diameter than stock. I have no rubbing issues at all.
The Mach 1 replicas would look really nice. I don't know of anyone who has tried them on a 3rd gen, so the sizing an offset would be a question. They seem to usually be an 18 x 9 with about a +24mm offset, which would come clsoe to sticking outside the fender, if thats an issue for you.
The Cobra R replicas are really nice. I think dwtc is running those on his now. He used to have some bullitts on his, that I really liked.
There are some guys running some nice looking 20s. Look at Sarek's, Flik's, and Anabloic Frolic's for examples.
There's a guy on FXN, svosho, who is looking at some really nice Fittipaldi wheels for his Mountaineer.
Jeff I am getting the Cobra R in Chrome in the 20" I really like the look of the wheel but I think it will look better in Chrome, I wasnt happy with the silver wheel on my silver X with the grey bottom (too many different colors going on)