You can't compare yourself to small 2 man operations... you are a design/marketing firm. Most sign shops specializing in wraps (like 80-90%) are not all that great at design (or they are showing poop on their websites) and most throw the design in to sell the wrap. You are not a sign shop, can not compete with that, so you have to sell yourself on the better design that cost a little more. You may not have to compete with the 100+ sign shops that wrap or the 500+ design firms in the area. You are really selling yourself and your companies skills. If you are competing on or worrying about the competition's price... get out of wraps, raise your rates because they are worth it, or realize that the profit can be slim.
The options I see are...
-- Design it and send it to a competent shop to work out the final details.
-- Design the wrap and partner with a wrap shop.
-- Or become a sign shop and hire a designer specializes in wraps that has a printer and can install and make up the money on the print and install
I only design, I can't compete with sign shops either... so I don't. I'm a decent designer and my work stands out. I'm looking for clients that want better than the average sign shop.
I saw this book the other day, and ordered it, it's not about your original question, but it is about justifying your worth... might be worth a look.
http://www.amazon.com/gp/product/0321844920/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER