deskthority

There's quite a lot of options out there for WKL boards, but I'm not sure you're going to find much in the way of in-stock items that will work with those caps. I'd say keep an eye out for group buys you fancy on Geekhack. I know a friend of mine is planning to IC a stacked acrylic board quite soon....

SP SA keycaps are probably the smoothest stock caps I've ever seen. You can really take any ABS set and polish the surface and that'll result in a textureless keycap.

Alpacas can't really be "made" in the sense that I think you mean. At the very least, any parts that you buy in order to make them would already be closer than any combination with Gateron parts. Any Durock or Everglide linear with Gateron yellow springs would be your best bet, I think.