One of my friends emailed this theory earlier, and I loved it, so I got his permission to post it:
"So, if Ben can time travel, talk to or see a man in a mysterious cabin that appears and disappears...and came out of his hidden room 'dirty'...could it be that he can manifest himself as the Smoke Monster? His character was obviously cast to trick us in the early going, as somewhat surprising physically (wimpy, eggheaded)...not the physical force we've come to know him as.I guess the question is, have we ever seen Ben and the Smoke Monster in the same shot? He didn't come jumping out of the weeds until the smoke monster furor had ended...and the monster seems to treat people like he does. It inspected/watched Locke, killed the pilot (who we know is important because the helicopter pilot knew he was too good to crash a plane from their past together), nuzzled up to Kate as if to sniff her out and determine if she was good or bad (since he didn't get a good read on her at breakfast)...Perhaps Ben can do more than transport himself in time. When on the island and super pissed, he can get his Smoke Monster on. In the early Smoke Monster moments, it didn't show itself, but rather tried to scare everyone to stay on the beach...stopping at the treelines...stay away from the center of the island, where he and the others lived."
So...what do YOU think?