It's funny as I've worked in publishing a long time. 6 1/8 x 9 1/4 is a pretty standard book trim size. 40 copies is pretty short run, and at least one of the printers I would have used for a job like that has gone out of business. I haven't had to do a job like that in a while. But with a lot of printers offering super-short-run digital presses, I'd think it could be done without huge hassle.