I'm probably not the right guy to put this together, but my oldest swears by CustomInk.com for tee shirts. She had some made up for a college function and said they really have their s*** together, and make it easy. I'd be down for a XXL. http://www.customink.com/
Alternatively, maybe the Orvis shop could order a dozen each M, L, XL, XXL. That'd bring me in pronto.