Well I've seen some 17340 cells, But as i remember they were unprotected, I dont realy belive the capacity. espacially when they have a discalimer stating they are not realy that high capacity.
Also one of the types are "3V" whatever that means.
Protected cells are probably bordering on 17mm anyway because of the extra wire, but It would be nice to have some realy short fat cells with 1000mah real capacity.