yes got balsa from Germany , but needed some more and was a quick trip to Norwegian and the have some fine balsa but you have to hand pick , if they have to a complete biplane I dont know.
And I agree balsa wings on a biplane is to much job, its ok if you have a kit !
Foam I got from Coop Obs localy I have tried to get lighter foam order specially before buts its not possible , I had to ordrer big if I should get it was the answer.