Hard to find but proof is proof. Nice one Danny...
I've kept the image to the Pprune recommended size so it might be a bit unclear but if you follow the link below the image and then scroll down the page, you can click on original picture to get a large view of five Stearman's all being flown from the front.
Stearman History - Vintage Aeroplane Europe
Credit: Vintage Aeroplane Europe