Try Atherton Place Townhomes off Dave Lyle and Springsteen behind the Target shopping area. I would not call them upscale, but the neighborhood and location is good.
There are townhomes that are for sale there but are being offered for rent by owner.
What price range are you looking for? How many bedrooms?
I was with a friend looking for a nice apartment last year and saw a beautiful new development in Fort Mill. I can't think of the name right now but it is off of Springfield. It has upscale amenities!
Hope this helps...