Talked to the salesman/gm and he said they don't have a kit at this time but will let me know if he comes across one. Emailed kubota about it, may just end up making something work...famous last words" how hard can it be!"
I've been wondering if you could just buy a standard alternator from an autoparts store and rig it up. The Kubota uses a simple v-belt to drive and a pivoting alternator mount for tension. I bet you could adapt just about anything on there that is self-exciting.
Was considering that, just use a 1 wire setup, if I remember correctly there's 2 from the dynamo. Either run it to the battery or tie into the hot on the starter.
I have a concurrent thread to yours about upgrading to an alternator. I saw you posted to it but I don't know if you checked it lately. KyleH posted a kit with PN that is made for the B2630 (as well as some older models) and he says it fits perfectly. That PN is K7324. I have my dealer here getting me price and availability but I'm pretty excited to find a ready made kit.
It's pouring rain out today, so a bit dark but figured this would give an idea of what it looks like without pulling the tractor out and pulling the panels off in the rain. If there's something specific anybody wants a picture of just let me know and I'll see what I can do.