Bob my kubota B2781 is all gear, without any chain, gearbox in th center of auger. The pto shaft hooks ddirectly to the back of shaft that drives impeller and then through the gearbox to rotate the auger. My neighbour had a newer model kubota and it was just like RickB described. They are available.
I will say that my neighbours blower had a longer chute discharge distance than mine, I was told it was because his impeller rotated a little faster, maybe it was just newer.