I hadn't thought about doing this, but the mechanics should be pretty simple.
The design of the thumper would be the interesting part.
Two choices:
First option: remove the fan and internals from the lids, install the required pipework to transfer the vapour to the thumper. The thumper could be designed with whatever still was desired. The lid of the airstill would need to be held to assist with the slight increase pressure.
Second option: Manufacture a still head to fit the Airstill with all the pipework etc. Manufacture a thumper body that will fit the Airstill Lid. Then you will have a boiler unit and an air cooled thumper.
Lets know if you have a go.