came across these for a vintage Kubota - no affiliation
newhaven.craigslist.org

Kubota PTO clutch shaft and adaptor - farm & garden - by owner - sale - craigslist
Kubota front Crankshaft shaft and splined adaptor. This is the front shaft that comes off the engine crankshaft to power any mid-mount and front end impliments like the snowblower and mid mount...