I do not see this happeneing anytime soon.
There is not enough content for it yet. And even the announced upcoming channels would not comprise a top 50 package.
I think people are confusing that Dish said with the SuperDISH could offer up to 50 HD channels by the end of this year. However since the HD plans for the SuperDISH have been scrapped for now, it thros a monkey rench into things.