I have always been bothered by the fact that I could walk into Markarth in Forsworn armor or Solitude with Stormcloak armor on and no one seems to mind. If I'm dressed in ragged clothing the nobles and Jarls should look down their nose at me, or if I walk in public with shrouded or thieves guild armor people should be freaked out! The Riften guards react to thieves guild armor so I know it's possible, I'm curios if anyone has done something like this.

P.S. If someone is developing a mod like this it would be cool if people don't recognize you when you are wearing a mask or something that covers your face, but that would probably be more difficult.

Thievs and brotherhood people are already killed on sight, would you REALLY want that as normal play?

If you honestly do, then just get your bounty up hign enough so people attack you on sight, and presto, never have to change clothing again.

I see what you're saying, it just annoys me talking to Mjoll about how bad the thieves guild is while wearing my guild master armor. It feels like I'm walking around Compton dressed as a Crip. Normally I would switch to a set of fine clothing in cities so I felt "espionagy" but I'd like there to be consequences for dressing as a criminal or rival faction, immersion and all that.

This is something I would like as well.
It would actually give me a reason to wear the different types of clothes.

NPC's recognized clothes in Oblivion. Not in very many cases I don't think, but you'd draw reactions from your fellow mages if you walked around the College in a Necromancer's outfit, I think they would tell you to take them off or something (hehe) if you spoke to a Mage while wearing them.

I never played Oblivion, but something like that sounds like what I'm talking about. If someone expanded that script and put it in Skyrim I'd download it in a second.

I want this too.

When I played my thief character I always went into the bushes and took the armor off before entering a town. I kept thinking it would have been nice if NPC disposition dropped, say, 5 or 10 points if you had it on. In Morrowind NPC disposition dropped if you had a weapon out during a conversation. So it can be done!

Wouldn't it be rather easy to just add bounty value on Thieves Guild / Dark Brotherhood and Forsworn armors?

Edit: Yeah, the trickier part most likely will be to get rid of the bounty when not wearing those armors.
I wish I'd have time to do mods again... I'm way out of practice.

You could probably do something along the lines of a script adding you to a faction once you don that armour. The Forsworn, for example. I did this for my own game in Oblivion, Fallout 3, and Fallout NV but I haven't really looked into it in Skyrim. The whole script savegame embeding thing has put me off somewhat. I'm a little surprised that no-one seems to have taken this on as a mod as yet.

The most I've done was tweak some NPC responses to what the PC is wearing, like guards telling you that you're wearing brigands armour when you're wearing bandit/thief armours etc. And wearing some of the skimpy outfits will bring comments about how cold you must be, how what you're wearing won't be any good in a real fight, or to go put some clothes on. Small things amuse me.

Any time I hear that someone hasn't played Oblivion . . .