Right, The Libertine was not a wide release- I probably would've had a better idea last year, but I'm guessing it was in about ~500 theaters, in early spring '06 (after a one week Oscar run at the end of '05). I remember being worried about finding it in my area (DC suburbs), but it did play in several theaters here. However, the theaters were not anywhere near full. Just to say that a smaller film starring Johnny is still possible, even post-Pirates. And with how fickle our culture sometimes is with what's hot and what's not, one never knows for sure.
I hope you're right that Dark Shadows will be treated like a potential box office hit, and considering the loyalty of the DS fanbase all these years, it should get great financial backing and such. One of the big unknowns is that Johnny's production company, Infinitum Nihil, is still very new and has not actually gotten any films into production yet! So the waters are somewhat untested. But Shantaram, one of Infinitum Nihil's first if not THE first, which will star Johnny and will start filming in January, sounds like it has a pretty big production budget- they'll be doing a lot of the filming on location in India.
As for another Pirates movie, bite your tongue
Just kidding- while I love the Pirates films, I am a little concerned about overkill and the fact that they've already taken up so much of Johnny's time- I'd rather see him do a variety of things (like DS)! Yet, after seeing At World's End, I found myself thinking that a sequel with Captain Jack and Barbossa might be fun, after all! But I hope it doesn't happen for quite a few years.