20 lb trailer to haul 3lb of clothes. Sounds counter productive to me.
Even a BOB weighs in at 17lb. Then we get to the whole "well I got plenty of room" aspect where you end up hauling 10lb of extra junk you really dont need. After 3 years of Commuting I have gone less is more and that steep hill is sure a lot easier to deal with now LOL. I am fortunate in that I work in a place where shorts are acceptable.
If you don't wear a suit for the 9-5 I would say just pick clothes that are fairly wrinkle free and go with panniers.
there are hanging panniers that flip over the whole rack for carrying suits. Cant seem to find a link at the moment but one of those and a steamer at the office to knock out the wrinkles would work. Some folks drive in one day a week to carry in their weekly clothes need and ride the other 4 days.