It's not often I find a new calorie dense food that I actually like. I discovered Frontier Bites at a trail run recently and have been pretty impressed by them. Light and crunchy and pack around 150-160 cals/oz. Imagine crossing a rice cake, with a honey stinger waffle, and sprinkling a few nuts in... that's pretty much what they're like.
These guys are more or less a cottage industry; they've mostly been marketing toward trail runners so I wanted to give them a shout out over here. I made a short blog post about them the other day (shameless blogspam)...