Have you inquired EK about re-stocking the KBs?
Using both polite and courteous dialog I was able elicit responses to my inquiries previously sent to EK.
Sometimes I think they won't share information if it gives away too much detail as a need to know basis.
But in this case, expressing a sincere interest to purchase a 104ub 55g from them should be sufficient.
GL.
EDIT: my mistake, there's no 55g edition with English keycaps for the 104u
You may have better success with buying a 104u and do a 55g donor swap from other RF keyboards. Then resell the donor keyboards. Many ppl here have gone this route.