I'm not aware of anyone who makes one, I would think a chainsaw would be easier and safer, but the cordwood saw shouldn't be to hard to make. The hardest part would be powering it, but that shouldn't be hard either.
We normally called it a buzz saw, so there may be some confusion. Spent many an hour running wood through them in the day.
They are listed on eBay and CL once in awhile. There are a number around, but as mentioned the chainsaw working over the pile of sticks would be faster. Some think they are dangerous but not moreso than other equipment (such as a chainsaw ).
Once the wood is in a neat pile like the video shows, then at least one extra person to keep the saw operator busy helps a great deal. Same as a helper tossing sticks up on a sawhorse for a chainsaw operator to buzz off would be faster.
That buzz saw shown in the video needs a good sharpening. Should zi-ing through that small wood much quicker than it is shown.
Building one shouldn't be a problem if you can find the saw blade to start with. Now they are usually converted over to PTO shaft power.
Fordson Major Diesel, McCormick Deering W4, Ford 1510, John Deere L111
I don't have any plans, but I do have a link to the only company that I'm aware of who still builds cord-wood saws. Here you go: Vermont Woodsman Buzz Saw
I grew up working with a saw powered by my dad's John Deere A. Cut lots of wood in very little time.
Good luck.
I found an old self powered unit on CL. ($75) Used a pto rt angle gear box from a spreader ($35) a shaft, some bearings and pulleys($45) some angle stock lying around and now i have a pto unit that cuts wood like butter