I'm not talking grilling. I'm talking low & slow in the smoker or pit for several hours. Can it be done and, if so, which vegetables (or fruits) could be adapted to it?
I've had smoked cabbage and loved it. Smoked taters came out a bit dry and over-cooked. They cooked kinda funny and the extensive time did something weird with the starch so they almost had a "reheated" quality to them.
If you smoke tomatoes on a sheet pan, then use them in pasta, it adds a ton of flavor and a little bit goes a long ways. The same is true for eggplant. You can make a wonderful pasta sauce with smoked tomatoes, eggplants, zucchini, and garlic.
There's a restaurant I've seen on tv that uses smoked tomatoes in their salad dressing. That sounded like something I need to try as well.
I'd like to use some smoked eggplant in baba ganoush one day.
I wouldn't smoke a fruit, but now I'm wondering how awesome it would be to smoke a pineapple and use it in ice cream.
As somebody already pointed out, you'll want something that is sturdy, or you'll need to have a hard smoke with lower heat for a short period of time. Otherwise, you'll just end up with mush. Mush can be useful, depending upon the recipe, though.