I know this is an old thread, but I think your best idea would be to give a price for a finished product (you get the meat, smoke, pull/slice, etc.), and don't let them bring you their meat. Not only are you apparently going up against prices that you can't (won't) match, there is a perception reason that you're getting the reactions you do.
I've been in sales my whole life (well, since college), and you're not selling something that your customers view as valuable. Right now, you're selling a service. What is that service? Cooking. We all know what goes into that service, but your customer doesn't (and doesn't care, most likely). They just think you're cooking. They don't know how much fuel you'll go through in your smoke, nor does that really matter to them.
What you CAN do to make sure you're getting a price you're comfortable with, and selling something of value to your customers is to eliminate all work for them. They don't have to go to the store, buy the meat, take it somewhere, come back 15 hours later to pick it up and drive it home just to slice/pull it themselves. Sell them a "Whole 8lb Pork Shoulder Roast - seasoned, slow smoked, and either pulled or sliced" for however much you want to charge.
Say it's $30. To your customer they can pay you $20 and just go pick up the meat, or they can go buy it at the store for about $16 plus tax (I know some people get them less, it seems like I always pay $1.99/lb, even at Costco), plus then they have to take it to the buck-a-pound a guy, leave, find something to do for 15 hours, come back, take it home, slice/pull it. and they spent a total of about $28 (rounded tax). Or, for $30 they can show up when it's done, take it home and eat dinner.
That's $2 well spent, isn't it? Plus, if you can get a better deal at Costco, Sam's, RD, whatever in your area, then you're profit just went from $14 - fuel/rub, etc to however much.
Also, people don't pay attention to what kind of meat they buy. However, if you play up using "High Quality" whatever grade meat you use, then that has more value, because people think that's better than they would get at the store, weather it is or not. Whatever info you can get from the meat you would buy, use it. Locally bred? Great! Do you get it from a local butcher that's been in business for a long time? Use it (long business success = quality to many people). Enhanced ribs? Tell them! Before you got into this, did you know what enhanced meant? If you're like me, you probably that enhanced meant better!! It's all in how you spin it.
Don't forget your own "secret" rub that will have their guests begging for their recipe!
I have been thinking about starting a catering company at some point, and I have a friend loosely involved in it, and as we talk about it I'm amazed at the apparent lack of salesmanship involved in a lot of these companies.
If you can't sell your product/services then you have to compete on price. If you compete on price, you won't survive, because there's always someone with a pencil who will beat that price.