I have a few dream ones, but I am pretty sure nowhere near enough people would want them to make them feasible cost wise.
1. doubleshots 37 set with Russian Cyrillic legend ONLY, no Latin, aligned bottom right, bright orange on cream. Instead of arrow, the extra 4 would be cream on orange for the цфыв keys.
2. 104 US ANSI doubleshot set done up typing tutor style, with CMYK colorway, cyan on black for vowels, magenta on black for consonants, yellow on black for punctuation and numbers, black on c,m,y for different keys for rest. All in some custom font, maybe kravitz rounded.
Of course there is a lot of random 'novelty' type ones I think would be amusing, but pretty much always in passing. Hammer and Sickle modifier yellow on red is still one I have been wanting for a while though as winkey replacement.