Yeah bethblog said more info is coming at E3.
By the way, what's DCL? DownContentLoadable?
Yes, you are correct there are about 4-5 to be exact. LOL Anyway to answer your question it will be sometime this summer. The only official announcement so far was the name, DawnGuard, which everyone already knew because of the copyrighting of that name. I posted that originally. The next official announcement with hopefully more information will be at E3 next month.