http://vgtact.com/showthread.php?t=2308
And Aruspex has also mentioned a garment bag.
Weight hasn't been an issue for me, but space has, and I'm only doing adventuring and diplomacy right now, mostly diplomacy. I carry 2 alternate pieces of adventuring gear and I have a few quest items in my bags. Everything else I have is for diplomacy.
The bottom line is that diplomacy items take up a LOT of room. Crafters have a special bag for their utilities. Likewise diplomats should, and will, have a special bag for their clothing.