yeah there is a big discrepancy between the terms. the saw you have pictured can be listed as a frame saw , bow saw , or stretcher saw. personally i think it is a bow saw , because technically a bow saw is stretched , but whatever...
i dont recall how i came upon it , but a lot of boat builders use it , basically to get two boards (or more) from one.
the one i showed lacked an alignment block. some of them have pieces on the end of the blade , with a vertical , or angled slice in it , that the blade sits in. this keeps the blade from twisting. one variant had the above mentioned angled slice , and was used with some kind of fence to produce veneer size cuts.
im waitin on some wide bandsaw blade from a member , once it gets here , ill do a build and use-along so you can see it.
theres lots of stuff on the net if you cant wait.
-hov