At this point, I'm doing it in-house. I print to light cardstock, then laminate with 5 mil heavy laminant on both sides, if I could afford to do it on gameboard stock I would, but I'm afraid that would be cost prohibitive to sell. In the state I have them now, I might be able to get the price under $15, many less, and it would be cheaper to mail in this format, just an envelope that's big enough and some protective cardboard on either side.
While I see the mathmatical increase by making them square, the cheapest way for me to produce them is at 11 x 17, and the extra inches in the rectangular shape becomes needed real estate to get more details. The tighter space, the less room I can create interesting detail. If I could print them 17" x 17" now that would be something, but in making it a product I can produce in-house - the size and format is how they will exist for the time being.
Someone else tried to suggest, what about purchasing two sets, then the number of Endless Terrain layouts is exponentially greater. Thanks, Old Guy, somebody once calculated the number of permutations (6144), but I had forgotten. Remember I may be technically skilled to create professional maps, I am really an artist, and not a mathmetician/scientist - glad you did, cause I didn't want to!
I was thinking I could place polls on the site where the community could vote for which map gets produced next, as well as ideas for future free maps and map sets. Offer contests for best map idea, etc.
And if the number of orders for the map got crazy (always such a hope), I have printer-only sources to get volume printing on standard presses to meet any excessive demand. If I don't get crazy amounts of orders, I can do it in-house - I never have to keep an inventory, I essentially POD them myself one order at a time.