CraigR. said "A Granny suite is usually a basement suite in a house with a seperate entrance, an ADU from my understanding is akin to a guest house. If that's the option you're looking for, there is a few places over by the university, around 15 Street and Victoria that had guest houses put in around fifteen years ago or so. Make sure you do your homeowrk with building codes etc., as I seem to remember a stink about guest houses around that same time. "
The City recently made changes to the Zoning By-law that make building detached accessory suites easier than ever before.
With that said, not may have taken advantage of the new rules. I suspect that servicing a second building with only one unit can be somewhat cost prohibitive compared to converting a basement to a suite.