These are not Skill capped at 20. I made three items last night:
San d'Orian Boots San d'Orian Gloves San d'Orian Vest
My leathercraft is at 22 and I got a skill up on each one of these items. The Vest was extremely difficult to make and I assume it has a higher cap than the other items in the set.
It's an upgrade craft from the Royal footman's vest obtained from conquest points. The recipe is somewhat new and I haven't figured it out. It's the +1 version of the Royal footmans vest. there is a +2 version too. As you can tell by the white circle behind the icon.