I've done this before, it's obviously easier on a bike without recessed brake mounts. For a bike that does have recessed brake mounts, what I did was fit a schrader-to-presta adapter to take up the void, and using a recessed brake mount front brake on the rear. The bolt length is just right. Did that make sense?

In my use it did actually end up improving braking. I also found it helpful to get the cables out of the way of a large saddlebag. If you've got a bike you feel like tinkering on I say go for it, I found zero negatives beyond needing the parts in question.