My reasons for trying to find this out in the first place...
I see a lot of potential for dynamic blocks in my current position. But I know that, in this case (something like receptacles) my users won't stand with having to insert a receptacle and then change it to the appropriate type.
I want to be able to setup a palette with each variation and, when they select it, it changes to the appropriate setting.
One of the major advantages I see with dynamic blocks, as I believe was the intent, is the elimination of so many blocks that are all similar. When I asked the rep from Autodesk if this was possible, he gave me a blank stare. I was worried that something like that might not be possible.