I'm trying to find a 26mm ahead stem so I can build it up. I just called up an LBS and asked and they said
"Oh, you mean 25.4"
"No, that will be too small, I need 26mm"
"It will be fine, they only come in 25.4mm and 31.8mm. Most bikes now take oversize anyway so that's probably what you need"
Bye then.
Nitto shims solve the 25.4-26mm problem, you know.
LoL.