Try smoking them at 230-240 degrees for about 2 hours. If you want to make it easy just use portabela mushrooms and scrape out the gills to allow for more stuffing. I topped mine with fresh marinated mozerella cheese balls. Be creative.
I have done shrooms with a cream cheese based filling then wrapped a piece of bacon around them and smoke them.... they are awesome! My wife can't to ABT's (she's a spice wimp), so I do ABT's for me and shrooms for her.
Yes I have done this both in the smoker and in the oven. I mix a brick of cream cheese, a log of Jimmy deans sausage (browned, and some onion. I use this same mix in my mushrooms and in my ABT's. I just smoke them until they look done. I am usually throwing them in while I am smoking something else so some times they are at 225 degrees and some times they are at 300 degrees. I just go by looks as everything is already cooked. We love them!