KWA/KSC MP7 butt plate
 

No matter where I look, I can't find one. The KWA USA proshop doesn't have any.

As far as I am aware KWA is done with the MP7 and all items related to it.
Sorry but I do not know where else you can get the item you are looking for.

call them direct and speak to them on the phone they often have parts that aren't listed on the website.

+1 to what P.Phresh suggested, had an issue finding a spring for my MK23 and had to e-mail them. They messaged me back with price and cost of shipping, which in my case was about $0.50 for the part and almost $9 for shipping.

Part #119?