I used to work in shipping, and yeah the cardboard really does suck the moisture out of your hands!
I LOVE Burt's Bees products, so I'll second the Burt's. My husband and I both have problems with our hands getting so dry they crack and bleed, so what we use is the Burt's Bees hand SALVE. It does feel greasy for awhile until it soaks in, so it's not a "rub it on real quick and get back to work" thing, but it really works well. I think my advice would be to get the Burt's hand cream and use that throughout the day, but use the salve at night to really condition your hands.
Best wishes finding a solution. Cracked hands are a drag.