I might have a solution for you. This is what I want to get for my commuter.

Trek has a rack called the Interchange. It's a regular rack that fits regular trunks and panniers BUT, it also fits the Interchange stuff which snaps on and off super easy. My husband has one and uses the interchange panniers for his commute. I'm going to get one because I want to get the rear basket. It snaps on and off and has a handle to carry around the grocery store or farmers market! I'm pretty sure I'll be able to use this basket AND my panniers at the same time.