Of course, you know there are two existing non-WDW
DVC resorts, Hilton Head and Vero Beach.
Other locations had been planned, and land purchased in Newport Beach, CA. In fact, the resort was announced by DVC years ago. However, because sales were slow at the Hilton Head and Vero Beach resorts (in fact, Vero was intended to be a much larger resort than it is, and "extra" land was sold off), Newport was never built, and the location sold to another company (Marriott, I think).
As to whether there will ever be any non-WDW locations in the future, we really don't know at this time. A
DisneyLAND location is rumored to be in the works, but no official word from DVC. WDW seems to be the most popular destination for DVC owners, and I imagine most of the future construction will be located there.
You can trade to other locations through Interval International, or rent out your points and use the proceeds to visit other destinations.