Blue sumatras have been around, just not commonly.  Blue Sumatra LF were just admitted to the APA Standard of Perfection in the past decade or so.  Tom Kernan, Pres. of the Sumatra Association, has outstanding blues in LF and bantam.

Sumatras, even black weren't shown much or at all back in the 1950's and 60's, according to a friend who spent his summers traveling with his dad, a stringman (one who showed hundreds of chickens at each show to earn a profit) from fair to fair in several states back in those years.

No