That particular blower was built from an MTD 2 stage with a 10 hp B&S engine. Rejean (he is up by CFB ValCartier) built it himself. Rick Prentice aka billieandmillie has also built a snowblower for his cub. Remember that the Cub must be use only as the motive force, it cannot be used as both the motive and the blower power source as there just isn't enough power to blow effectively when moving slowly enough to properly blow the snow. An auxillary engine must be used. Danco knew this way back in the late 50's early 60's when they built their snow thrower for the Cub.
I am in the process of building my own as well. Finding a suitably sized MTD style 2 stage blower was proving difficult. I was going to used 2 26" to 28" blower cages, weld together on a frame, add a single power source, chain drive for the auger and impellers and blow out twin chutes. Still a good idea and one I may build eventually, but it looks like I may have found a 52" MTD blower for my Cub just up the street. So we shall see.
Where exactly in snow country are you from? I am originally from Timmins and now live in Dieppe. Last winter we got over 500cm's of snow over the course of the winter, so yeah.... we need blowers.
I am trying to find Ricks thread on his blower project, but not having a lot of luck at the moment. Will search after I get in from the garden.