Kaysie's comment makes me think of an idea - why not a claendar and then put together a poster book or even a coffe table-esque book?
The pics shown here are magnificent, both in quality and subject. The talent represented here is extraordinary. I could see a line of posters being quite popular in multiple venues - hobbyists, serious students, educators, environmental activists, etc. But I really would be grateful for a more standard sized calendar - but whatever size is selected, I will be a buyer. Last year's were a big hit.