650C/26x1"/ISO571 might be more what you want. This was always the go fast 26" size. It's not as retro hip as 650B, but it's still common enough that you could probably get a pretty light wheelset. Used to be a tubular version too, but not sure rims are still sold. Haven't kept up.

650B was historically a utility/touring size. It kind of still is. Even so, 32h A23 650B wheels with light tires could be OK.