FWIW, I own the 20" Superlight Briggs rollerboard ("Baseline 20" Superlight Upright Carry-On" says the offical product description).

It's good for 3-4 day trips. And, yes, I have the same issue of having to carry both running and dress shoes while traveling. Never really figured out a good solution to that one.

In any case, as I mentioned in another thread, the 20" is a good suitcase and packs a lot more than I thought it would.