No, this was just off the top of my head at the time. I had forgotten all about it until I received an email notification of your reply (which I must say, is a handy forum feature).
I had the idea that perhaps you could create an additional enclosure around the barrel of your rocket heater, and gasify wood with the heat produced, then you could feed the gas into the burn chamber.
I've attached a picture to demonstrate.
I think the biggest challenge with this approach would be to ensure the exhaust temperature was still low enough. Possibly adding fins between the shroud and barrel would allow more heat to be pulled out.
