We've already started reaching out to other keyboard makers, and the response has been enthusiastic. We'll be announcing more details as deals are made.
Having said that, the people they really want to hear from are customers. If customers start asking for it, it'll happen -- so feel free to reach out them yourselves. Good ideas only get propagated if the fans express their wishes.
Regarding PBT caps, what we've been told so far is that PBT material is not widely available in China, and that PBT caps are all made in Taiwan using some special process. Will keep you posted as we learn more.
We'll look into Dyesub printing as well, but that's less likely. We currently use either laser or UV printing, both of which are pretty much impervious to rubbing off.