One that I really want that I am so sad I missed out on is the Spyderco Kumo.
They need to do a Kumo sprint run because I feel like I missed out on the Kumo big time.
That is truly about the most obscure Spyderco fixed blade>> the KUMO was a nice design overall but I didn't like the cordage handle that Spyderco did it with. That would be a most interesting Sprint Run with one of the newer supersteels and possibly a Carbon Fiber ( first choice) or G-10 handle. I would not want a Sprint Run in it's original format>> Sorry
Another very obscure fixed blade that you rarely even hear talked about was their SPOT model. It had a very small blade but it was a most interesting collector's piece if nothing else.