Hello and welcome, John That loader would be for a 20-30 year old tractor so you're not likely to find very many of them showing up on Craigslist or whatever. Never say never, so keep looking, but it would be a very lucky find if one turned up.
There are tractor salvage yards you can find with a Google search; some even specialize in Kubota. Those might be your best bet. And there is probably some long-time Kubota dealer who has had a new one sitting on their back lot for years, but who knows how to locate that dealer?
Good luck in your search.