So I composed my own skill list, and introduced Attainments to cover the things that I want to track, and even use to modify skill checks, but that I wouldn't classify as skills. I've talked about the resolution mechanic of Quintessence before; Attainments are scaled like task bonuses and are often appropriate to use as such. (I'm not 100% satisfied with this, and it may need some alteration - but this is a design blog, y'all, I don't claim to get it right the first time.)
Each skill is made up of three or more Tasks - specific applications of the skill, allowing characters to further specialize. The Tasks also say a variety of things about what I expect a Dust to Dust tabletop game might involve; many of these would be unusual choices for other settings. The actual text includes more discussion of each Task's coverage, but I don't want this post to become unbelievably long, so I've cut that text for now. (Also, some Task names are ambiguous or misleading without that text; filing "Plot a Route" under Acrobatics seems weird until you get that I'm talking about studying an area for acrobatic passage, more or less like studying an area in one of the Assassin's Creed games.) There are plenty of valid arguments to be made that some two tasks should be collapsed together, also. Tasks include recommended ability score modifiers; the ability scores of QoD are Strength, Agility, Vitality, Intellect, Wisdom, and Spirit.
Easy checks use Action Difficulty 5.
Normal checks use AD 9.
Hard checks use AD 13.
Very Hard checks use AD 17.
Legendary checks use AD 21.