- Animal Training and Handling
- Armor Making
- Knowledge (specific area)
I think this will turn out better than the non-weapon proficiency system in the Dungeoneers and Wilderness Survival Guides, for the reason that those two books just gave characters slots for proficiencies as they rose in level, automatically. So players (at least in my experience) were left to keep filling up the slots with proficiencies just for the sake of doing so, leading to characters walking around like Christmas trees decked out with all sorts of non-sensical non-weapon proficiencies, just because they had to fill the slots. In the Emprise™ system, taking secondary skills is not only a conscious decision, but one that drains x.p., so it's a real choice.
Bear in mind that the skill system isn't exclusive; that is, it is not the case that unless you have taken the seamanship (swimming) skill, you can't swim. (Well, that might apply to something like alchemy, but that's a special case, and common sense must prevail.) But characters that have invested in an actual skill level in something are recognized to be better at that thing, and so could swim longer, or faster, or deeper, than someone who had not taken the skill level.
And as a bonus, it forms the basis of the NPC hireling system. Win-win!