According to an article in today's USA Today, "major hotel chains are building two hotels on one property, some in the the same building, that target two very different clienteles". The examples given for Marriott properties included a combined Residence Inn/Renaissance hotel in Alexandria, VA. A Residence Inn/Courtyard is under development near the L.A. Live complex in downtown in Los Angeles near the JW Marriott/Ritz Carlton which already share space in one property. The article also describes a Courtyard/Residence Inn that will open later this year near Manhattan's Central Park. The Courtyard will include floors 6-32 and the Residence Inn will include floors 36-64. Shared spaces include the fitness center, retail space, a restaurant, lounge, and outdoor seating overlooking Broadway.
I remember staying in a downtown Marriott property in Austin, Texas where a Courtyard and a Residence Inn were in the same building. I also remember several locations where 2 or 3 Marriott properties were very cose together, but did not share facilities.