The saws are everywhere around here... I bought it at a local flea market. I have seen them on ebay if you can't find one... search crosscut or two man saw.
The back seats are the floor. May throw in a cushion later on, but I angled the floor/notch so that it would be somewhat comfortable.
I appreciate all the comments! They really help keep me motivated! Gotta have this thing ready for the road in the spring!