Yes actually very much like those old typewriter key, but a square top like that one's shift key... very minimalist but much more modern looking. From the top you could see the switch stem so it would look kind of like [ + ]
Ideally they would be basically symmetric so can work well on either horizontal or vertical key. All same kind of profile to make even strangest custom layout possible. I was thinking it would make the number of unique key shapes very much smaller that way so it would be easier to produce. Just need the basics 1x1, 1x1.25, 1x1.5, 1x1.75, 1x2, 1x2.25, 1x2.75, and any spacebar size needed 3x - whatever.