Thanks for the question. This is actually Ikea cabinetry - the finish has been discontinued but the sizing is still the same. The clients determined the kick height so that the final cabinetry sits just shy of the ceiling.

Contact a local custom cabinet maker. They should be able to make those no problem. It will probably cost a bit more than a store piece but you know it's gonna be sized perfectly for your place and there aren't gonna be any ugly filler pieces which show up even more when you do a wall unit with zero clearance cabinetry.