By this definition of single handed opening by centrifugal force, is there a knife which is legal?
By the sounds of it, I think I'd stick with a traditional non-locking SAK or Leatherman Juice. For a locking blade, I'm wondering if something like the Leatherman Rebar or Super Tool 300 would be okay (the blades are on the inside, so you need to open the pliers to get at the blade first).