If we've opened the door to small/medium fixed blades and various carry options, then the Dozier-Crotts horizontal kydex sheath immediately jumps into suggestion land. There are plenty of blade styles and handle combinations available. The kydex sheath retains securely and the knife can be returned to the sheath guided by one's index finger. Winkler II kydex and Jim 'Treeman' Behring's kydex sheaths for the 'Pathfinder' and 'Recon Hunter' models also come to mind. Ah, choices, choices.....