my b i figured this type of stuff was public info. sites like kbdfans, and basically any other mechanical keyboard parts distributor out of china, should have a replacement base that can fit the pcb and plate. you probably won't find the exact same one, but you'll have options and as long as it fits the pcb and the plate (which you can check by seeing if the screw holes line up with the pcb, that it fits the same size keyb that your pcb is, and by making sure that the case accepts a plate).
KBDfans is the biggest one of these sites, but it offers slightly higher end stuff so you mght not find a cheap plastic case, but they'll have options that will fit. if you want the exact thing that's still probably possible but you'll have to do some digging around other sites.