KBDfans is the go-to store custom keyboard parts. I know they have at least had a matching PCB in stock. Beware that with hot-swapping sockets, you typically don't get any options for different keyboard layouts, so be sure to check that.
60% isn't really my thing, but I have seen a bunch of different cases here and there that are transparent, at different price points. Most have been frosted.
The classic 60% mechanical keyboard is a "tray mount": the case is an open tray that the keyboard PCB and (optional) plate is put into from the top: The PCB is sitting on standoffs on the case. Some more expensive cases have the plate mounted to the case, with the PCB hanging from the switches.