Here is my very cheap (albeit temporary...I'm saving for a Xtracycle) solution to the "how to get the dog and catfood that don't fit in the panniers home" problem. This is for the kind of person who would mount a milk crate on their bike and not be embarrassed...

The grocery cart was $10 at the Thrift Store and a bag of 40 zip ties was 99 cents. I do this every two months...about 2 miles round trip on quiet suburban streets. Total weight 45 pounds. After reading this thread I think that I'll put a flag on it for greater visability.