Sorry I can't help on the lunch front. I buy my lunch at work.

On the clothes front you could try this.

1. Leave your shoes, belt and ties at work.
2. Neatly fold your shirt and pants and use a pannier or rack trunk. Don't forget underwear and socks. If you have space you could also leave a couple pair of pants at work. I have two pair hanging in my office most of the time.
3. Return home with dirty clothes.

I actually use a small LL Bean Adventure Duffel strapped to my rear rack instead of panniers.
http://www.llbean.com/webapp/wcs/sto...p&feat=4522-tn

Try out as many options as you can and then make the call.

Cheers,