It seems you may have forgotten the most popular 40% layout (minivan/jetvan). The most common uses a row 2 1.75u backspace, row 3 1.25u tab and row 3 1.5u enter. Sometimes kits that support Minivan will also include a row 2 escape but that's also less common.
It looks like you've already got a row 2 escape, row 3 1.25u tab, and row 3 1.5u enter though, so all that would be missing is the 1.75u row 2 backspace.
If you include that, I'm definitely interested!