I believe they were run through Massdrop initially, but KeyClack has some leftover base kits.
https://www.keyclack.com/product/gmkplum
WOW! The price tag is heavy
Is it? I can't ever tell.
Seems like most GMK GBs these days hover around $150, so I figured $160 wasn't too bad for leftovers.
Now, if you really want to see heavy prices, you should check out Originative:
https://www.originativeco.com/collections/keysets.
The price isn't bad at all. I've ordered sets from Signature Plastics:
First the base set, then the modifiers, add the numpad kit, and the colorway kit, ahhh... don't forget the ISO add on kit, and the extra spacebars, yadda...yadda. I'm typing right now on the
Ice Cap set, which is really nice, but I don't think about the cost.
This Plum set is a full meal deal. One price, one purchase and you get every cap in the set. You get so many caps they won't all fit in the tray. And having all the extra caps is handy if you're trying to cover an oddball keyboard...