Check into a local starter repair shop. My local shop found a starter for my Mitsubishi D2350. I was suitably amazed. It seems many of the Japanese starters interchange if you know what fits what.
If you can a picture of Denso part number 128000-8460 starter some locations list that as a replacement and as someone has already stated alot of the Japanese brand will interchange this by the picture calls for it fitting a kubota.