So I just got to chapter 2 and I have yet to find any armor I can add enhancements to... Have I completely missed something?

There was the piece of armour you could grab from a chest in the Sheriff's fortress. Also I believe the troll gives you schematics for an armour that might be upgradeable.

You can craft them, not sure how to know if an armor/wep will have slots but every item i crafted had slots, one or more.

I'm wearing some +6 heavy leather I crafted and it has no slots.

...Did the troll DROP a schematic? because I completed that quest without killing him and I don't recall a schematic.

You have to give him his wife's head to get the armour.

I'm in chapter two and just found myself with two sets of armor with slots. Received both as a part of the main quest, so I'm betting you'll find yourself with some very soon.

Ah :( ...Sendel offered to play a game of dice for it but I never actually got the dialogue option for that. Bugger.