Stan, it depends on which side of the "pond" you are, If the US someone played a rather splendid one at the Getaway, so maybe they ,or one of the other attendees can point you in the right direction for a source.
If UK based, try an old fashioned hardware store such as Batemans Famous Emporium in Hastings, E. Sussex, but UK skiffle basses were usually mabe from Tea chests,, esp the (rare)1/2 size about 18 inches high, and a broom handle, seemed to give the best results.