Carrying stuff on your bike can be hip if you look like you mean it. Panniers are for carrying a bit of stuff some of the time. A bike with a cargo platform like an Xtracycle or a Kona Ute or even with a big front carrying rack like this one is hip in my books because you've dedicated your bike as a carrying machine.

That said, panniers can be detached and loaded off bike, such as in a grocery store. Now you're showing the world how practical your biking life-style is even when off-bike which if if not hip should be.

In this case, go all the way with serious carrying capacity:

http://www.arkel-od.com/panniers/uti...asp?fl=1&site=

Maybe you could wheel this thing around on a little wheeled carrier (like airplane luggage) and when done fold and attach to carrier to the other side of the bike rack.