Andre's on Main Street is one of the premier bakeries in town. Sorry, no address handy. Should be easy to track down though.
If you're looking for a high quality grocery store cake,
Hen House, with several locations around the suburbs, is the high end chain in town. Comparable with Sunset Foods or Treasure Island at their peak. They have an outstanding bakery department.
Also, if you want to pay a lot of money for a cake, for no apparent reason, there is a Dean & DeLuca store in Overland Park, KS.
If anything else comes to mind, I'll post further info.
Buddy