I haven't but I will soon. If done right you can't tell from factory, and of course in many cases it's far superior to anything you'd get from the factory, it just depends. Many dealers use aftermarket leather anyway when they do customs. A complete job will probably run around $1200 +/- depending on a variety of factors but don't quote me on that. Here are some links for national companies involved with this although any good local auto upholstery shop can do this as well:
http://www.classicsofttrim.com
http://www.katzkin.com