It's too bad blanks aren't being manufactured anymore if that is the case. I use dvorak layout so blanks were the goto option when I got my Realforce board. Thankfully, the default caps are pretty dark anyway.
User18 is correct. Topre keycaps are not being manufactured to be sold separately anymore. My guess is that Topre has anticipated the new MX compatible Topre sliders (see Novatouch) and will soon play in that market too.
AFAIK, aftermarket topre caps aren't being manufactured at all anymore, not even by topre themselves. Unless someone has an idea as to where we would be able to get these made, I can't see this being very successful.
I checked every Topre distributor website, most of the popular keyboard/keycap enthusiast websites in KR/CN/JP/HK/USA, and combed a good 20 different Japanese shop websites for blanks, and the only set I was able to locate on any of them was a blank yellow set on iomania (and it's out of stock, probably has been for a long time). So if I had to guess, I'd say Topre isn't manufacturing blanks (or the pink set) currently, and even if we could locate some untapped resource that had them in stock, it's likely the available quantity would be too low to do a drop. Might run into the quantity issue on printed caps as well, but I figured I'd just make the poll and see what happened.