You should see the Emerson quick-open feature
If you haven't handled the Emersons, you should definitely
give them a thought. They have a very slick nock on their
exposed blade-back that purposely snags briefly on any pocket
edge when you pull the knife out, and causes the blade to
snap open faster than if it were a switchblade. Their site
has videos of it, and it works really well:
http://www.emersonknives.com/EK_Video_Vault_Index.html
If you haven't handled the Emersons, you should definitely
give them a thought. They have a very slick nock on their
exposed blade-back that purposely snags briefly on any pocket
edge when you pull the knife out, and causes the blade to
snap open faster than if it were a switchblade. Their site
has videos of it, and it works really well:
http://www.emersonknives.com/EK_Video_Vault_Index.html