I want buy KMAC Keyboard 356 or 456 and Metal Keycap

1. KMAC      maybe you should searching and waiting and catching at here (used market) ;)2. Metal Keycap      I don't know.. sorry..

for KMAC, 356 or 456,,You need to find someone from the marketplace(GH : classified, in Korean : 사고 팔고) who wants to sell it.or you need to post a thread on the marketplace and say you are looking for kmac, 356 or 456..for metal keycaps,,I would recommend you to search on ebay. I have seen a lot of sellers there selling metal keycaps.If you are having trouble with translations,,feel free to PM me( insomnesia ) on Geekhack or Deskthority(if you are GH  or DT user). I can help you with KoreanEnglish translation.just for your information, you need to have at least 150 points to access the kbdmania marketplace.

metal keycapshttp://www.techkeys.us/artisan-keys.php

But yeah, it is true that you can find Used or New or even Unassembled KMAC or KPAD or KMAC2 here much, much, much easier then anywhere else in the Earth. lolGood luck anyway. I don't have KMAC though.