OK. I can live with 20%, and even though I've never had a tractor loan I think that a few car loans paid off and a clean credit record may help.
Kubota's current financing options (including the 6.99%) look like they run out at years end. I've been sort of counting on the fact that they will be extended, or will come around again in the late Winter / early Spring, but I'm not sure if this will come true. On the other hand, maybe "Crazy Al" Greenspan will lower interest rates, and I'll get a smokin' deal! (It's good to dream).
Thanks to everybody for their help.