Your choice of knife with a custom sheath?
My experience with pocket fixed blades is that a deep carry sheath is difficult to find.
A trick I've used with success is to loop a few inches of bead chain through the bottom of a kydex sheath, and buckle the chain around the belt loop nearest to the pocket. This allows the knife to hang tip-up in my pocket. When I need it, I can just grab the sheath, pull it completely out and then draw the knife. It works for my Lil' Roughneck, it should work for any pocket-sized fixed blade.
The downsides to this is that the knife needs a sheath with a hole in the bottom, and it needs to fit around the knife very securely.