I made my own with 16.5 mm key spacing. And it uses low profile switches and needs very low profile caps due to the way I mounted the top plate. I didn't feel like the usual way of mounting a plate would be rigid enough with my tight spacing; there'd be very little material between the switches. So my plate is on top of the switch body, with circular holes for the stems.
Even the niche datcyl manuforms will support cheap keycaps (even if they might not be compatible with high-profile keycaps).