Solidworks (.sldprt) models of Signature Plastics' DSA MX keycaps.
DSA profile MX keycaps
This repo contains keycaps for Solidworks keyboard models/assemblies.
If you'd like to create another cap, open the 1u cap and edit the width in the first extrude. Stock 1u width is 18.415mm, so you'd want to change it to 18.415x__u. For the larger caps add another 1.03 modifier (eg. 18.415 x 6.25 x 1.03) to fix the gap inbetween caps.