That's the other edge of the blade with Busse, I'm afraid. They release production runs few and far between, leaving the market in a high demand mode constantly: good for them, bad for those of us who want Busse knives.
Here's a site that shows quite a few different models of Busse knives.
Bad Mojo Busse Knife List Sadly, you will have to go to the secondary market if you want to buy any previous production models, all at a premium, unless you get damned lucky. We're talking Ebay, Bladeforums, etc.
Do some research, see what all the "experts" have to say about it, then maybe take a chance if you find a wad of cash is burning a hole in your pocket.
I didn't say it was going to be easy, I did my time and paid the price, and will likely get more, but that's just me. When I find something that I know works, I don't mind the effort so much.