(Inspired by some experimental packing w/ the Night Flight.) My TB wallet is great -- has been my main wallet for a few years now, still going very strong. It can hold a huge wad of cards (incl. fat RFID office-entry card), some folded money, an SD card, etc.
What I'd like is one a small as possible that will still hold several cards (needn't be as many as the regular wallet), with a urethane (or otherwise clear) front. I think its main compartment coud be about half the size of the current wallet. One (or zero, but one would be nice) dividers, and as slim as it can be and still hold (let's say) half a dozen cards and a similar number of paper bills folded in 3ds.