[DouglasCole]

For what it's worth, Tonfa is one of those weapons that I think should be handled differently:

Using a tonfa as a baton, with the protruding handle either close to the hand or far away, would be shortsword skill, or a generic skill for 1H balanced weapons.

Using a tonfa griping by the handle would use the unarmed combat skill.

In either case, the special effects are relatively straight-forward from a GURPS sense: used with a 1H extended grip, you get a swung attack, and can use armed grappling (Skill-2) to capture with the protruding handle. The extra leverage and reach are benefits in and of themselves, but require learning a weapon skill to use properly.

The "use with martial arts skill" gives the ability to parry weapons at no penalty or risk of damage to the limb (it basically turns the limb into a striker), as well as treating punching attacks with the same bonus you get from brass knuckles, since you get that nice punching hard surface.

If you want to use a tonfa as a grappling aid based on Wrestling or Judo skill, that's cool too. Give a ST bonus or something to account for leverage. In TG you get a +2 per die control point bonus, but that's neither here nor there.

The key bit for Dungeon Fantasy RPG is to not require an extra skill; this is an enhancement to skills you already have. That keeps it simple while still providing nifty abilities, and not diluting the skills list.