I'm just going to arrange a crap/ton of common sense to start, concentrated from my brain and the thread.
Two things should affect how dwarves feel about their clothing situation:
1.) Their cultural values
2.) Their environment
1. has a wide variety of parts. There should probably be an ethic value for each bodypart type, maybe something like ETHIC:NUDE_X:Y], where X is UPPER/LOWER/HEAD/GRASP/STRIKE, and Y is an ethics value. There might also be something for gender, although that's a bit more complex and I'll get to that once I leave the CS stuff behind. On the other hand, that's five new tags per entity, which would of course screw up mods. What's the default ethics value?
2. has several parts, as well. If one mostly lives in an environment with smooth or constructed floors, it's fine to go shoeless, but if your current living quarters are hewn stone or normal ground, there'll be issues (unless the creature has NOPAIN). Ideally, there would be some way of determining if an area would probably have sticks or pebbles or manure on the ground, all of which would make shoes about mandatory, but "hewn stone or ground with stuff growing on it" works pretty well. Gloves would be preferred by those who are working with picks or axes or something, to help prevent raw hands and blisters and stuff. Hats are usually based on culture and personal preference, but something would be good for those who live in cold or windy areas (the former for warmth, the latter for keeping grit out of eyes). Finally, torso clothing would be based on temperature, mostly; as little as socially acceptable for hot areas, several layers for cold ones, somewhere in between for everything else.
Now, onto my ideas.
Obviously, the aforementioned [ETHIC:CLOTHE_X] tags. Also, as I mentioned, I'll talk about an idea for gender. Something like [CLOTHE_GENDER:V:W:X:Y:Z] could work. V would be the gender, W would be the clothes type, X would be the subtype (either ANY or a specific type, say to make dwarven men not want to wear dresses), Y is either MORE or LESS (the former meaning it's more needed, the latter meaning it's less bad to lack), and Z being a number. I'm a bit fuzzy on how the numbers would work, exactly, but it could be neat.
As always, I like the idea of things varying over time. A thousand years ago, you would be hard-pressed to find a European lady wearing pants, but now it's not even blinked at. For various reasons, ethics may change over time. For nudity, a prime consideration is climate. If a human nation starts out in an exceptionally hot desert, it might not mind if people ran about nude except for sandals. However, if it starts to move into colder areas, wearing loincloths, pants, or even shirts would become the norm more and more, especially if goblins conquered their desert holdings. If the humans moved back into their desert a few centuries later, say after the goblins were weakened in a war against elves or something, their ethics would probably have changed since dozens of generations had grown used to seeing each other clothed. Another possibility is diplomacy. If the dwarves (who for the purposes of this argument are scandalized by lacking body clothing or hats) might be able to convince the human diplomats to, for the love of Cog*, PLEASE put on some clothes. Over time, this tradition of wearing clothes when the dwarves are around might stick, so that humans who commonly interact with dwarves or who are in the same community might start wearing clothes as the norm. For both of these, the opposite could occur--moving to warmer climates and dispensing some level of nudity taboo, or (say) elves convincing other races to be more relaxed about wearing clothes (assuming elves don't mind nudity, it would be rather rude to request that the people kindly inviting you over put on some clothes, so they'd grow more accustomed to nudity over time), or both ways at once (more likely with the culture things). Finally, on a usually-smaller level, an impoverished area that can't afford/make clothes might slowly lose nudity taboos for clothing not required by the environment. If no one in Syrupfalls has had a shirt for a couple years, no one is going to mind anymore (except for migrants and traders, of course; that would be interesting).
*Cog is a dwarven deity, a name I think I'll use for in-game deities.