In the "sleeper hit" that is Thee Compleat Librum ov Gar'Udok's Necromantic Artes, I included a sidebar for the Khukuri (also known as the Kukri, depends where you pick it up).
I didn't stick straight to the size conversion from the Kukri, but aimed at some game balance. (Otherwise, if a small Kukri deals 1d6, then a medium deals 1d8 and a large would deal 2d6 - which is a boatload of damage witht he crit stats on the kukri).
Here is the sidebar, from the text of Necromancer's Legacy, the print edition of Thee Compleat Librum ov Gar'Udok's Necromantic Artes.
The Khukuri
(exotic weapon)
Khukuri are curved, bladed weapons based on the most primitive “hooked” swords. Because of the curvature and the heavy head, a Khukuri chops with exceptional strength, dealing significant damage when aimed properly. Full decapitations are not unknown using these weapons. Khukuri come in three sizes in game terms: Small blades (15 inches long), Medium blades (21 inches long) and the enormous 36 inch Large blade. All are exotic weapons.
Small Khukuri, 1d4 damage, critical range: 19-20/x3
Medium Khukuri, 1d6 damage, critical range: 19-20/x3
Large Khukuri, 2d4 damage, critical range: 19-20/x3