When I was in Culinary School they stressed the point of keeping your food cost at about 28%. Using that theory a $10 item should have a food cost of around $2.80, I'm sure you could reverse engineer that formula. If your meat costs $4 a portion then menu cost would be around $12. I'm not sure how labor/ rent/ insurance would figure in for a smoking business.
Here's an article breaking it down more extensively:
http://books.google.com/books?id=rVY1KP_57LEC&pg=RA2-PA...0RLt1nY#PRA2-PA20,M1When I redid the menus at my families restaurant, I found other area restaurants with similar menus and priced accordingly. You could call around to some BBQ guys and Caterers and get quotes to give you an idea.
Good Luck