One of my first smokes I did a boneless leg of lamb because my wife is Greek and I'm very familiar with cooking these. I get mine from Costco because they aren't gamey and they are reasonably priced ($4/lb). I make a paste of olive oil, yogurt (full strength, none of that fat-free or lite junk), granulated onion (it doesn't cake up like onion powder does), mint, oregano, salt, pepper and minced garlic. You can also try a little red wine, rosemary, cayenne, lemon zest or pepper, brown sugar, etc). I spoon the paste into the crevice made by the deboning, and the remainder I rub over the outside and let it sit overnight.
I also did about 15 large baking potatoes: I microwaved them for about 10 minutes to soften them up and make them absorb the smoke better, rubbed them with olive oil, salt and pepper and smoked them for about 2 1/2 hours. If they aren't done, you can finish them off inside the house at a higher temp since taters aren't sensitive like muscle fibers and connective tissues are.
You might try a fatty goose or farm-raised duck. My brother-in-law suggested smoking a cheapo ham to give it the premium flavor, but personally I'm addicted to the Costco ham in the red and gold foil package, since its smokey-sweet-salty flavor is outrageous. You could also try some mass-produced sausages like Johnsonville brats. They even sell those at the store...for a much higher price!
Check out Mainely Dave's 2004-05 blog about his smoking experiments. He did scallops, shrimp, jalapeno peppers, hamburgers etc, and he will certainly expand your imagination.....