As one of the winners, I'll admit I am thrilled with this idea!

And will gladly submit a high rez image of Flying 118.
I do see one problem though. You might find it rather difficult to include the Dec 2009 winner's photo (unless that month's voting was ended early enough to meet production deadlines) and still produce a calendar that serves any purpose in January of 2010 (what with layout, production, shipping times etc.) You might want to consider a sort of fiscal year of images, say Oct 08 - Sep 09. I know that sorta messes up the "Best of the Year" thing but that would insure that the January winner didn't get skipped over straight to February.
Also, choosing a cover should be left to the moderators and Adam and Ole (recusing anyone with an image among the monthly winners).
Mike