A few that come to mind:
Pepper Pike Club & The Country Club in Pepper Pike, OH (these two may have a small creek separating them)
Bob O'Link Golf Club & Sunset Valley Golf Club in Highland Park, IL
Mississauga G&CC & Credit Valley G&CC in Mississauga, ON *Edit, Mike beat me to this one above*
Cowboys Golf Club & Grapevine Golf Course in Grapevine, TX
Barton Creek Resort (C&C Course) & Lost Creek Country Club in Austin, TX
There are also a few of these in the Myrtle Beach area:
Wild Wing Plantation (Avocet) & Myrtle Beach National (King's North)
River Club & Tradition Golf Club
Azalea Sands Golf Club & Beachwood Golf Club