I was messing around with some photo stitching software and the Ferraris maps, just trying to see what I could come up with. I was so happy with the end result that I posted it at the Gumroads website as a "loss leader."
It's 46" x 31". It is also scaled at 25mm = 330m. I chose this scale because it will let you play a game like Blucher on a 4' x 3' (poster-size) surface. It works out to about 15km x 10km in area at this scale. Of course, you can treat it as having some other scale if you want. There are a few inevitable glitches in the stitching, but I think these are pretty minor considering the size of the final project. You should be able to print this out for under $20, then pop it under some plexiglas and play right off of it.
Designer and owner of Forward March Studios: The World's first comprehensive range of 3D printed historic miniatures.