Hi Nick,
I don't know if they are available in your part of the world, but this might fit - http://www.amazon.co.uk/Bigtrak-Can-Holder-Junior/dp/B005G3R4Z0
Been meaning to get one for my BigTrak. Also been meaning to make my BigTrak autonomous, but I only got it for Christmas, and I think it might be too soon to start tearing it apart.
Only problem with the can holder is that it'd need someone in the kitchen to put the can in.