You could use martial arts skill plus a martial arts combat style skill that incorporates a Weapon Kata option plus Additional Strike. Or, you could a weapon combat style that incorporates Additional Unarmed Attack.
In the former case, you end up using only two skills, your MA attack skill and the MA style skill. (You don't roll against the style but the OB in the MA skill is limited by it.) The weapon kata attack is made at a penalty (-20). There are some additional requirements for the style and it will probably need to be Advanced which means for many characters it will be a Restricted skill.
In the latter case, you use three skills: your weapon skill, your weapon style skill, and your unarmed combat skill. (Again, you don't actually roll against the style skill, it just limits the other two.) It could in principle be a basic style, which means it will have the DP cost of any other combat maneuver skill.
I also like the MAC. It does have some limitations but they are things that are fundamental to RMSS. (E.g. generally speaking, it is very limiting to try to pick up a new combat style later on, just like other combat maneuvers like mounted combat or TWC.) Aside from those limitations, it is very well done.
