With my initial sketch I was envisaging using PVC pipe as the container for the can, but it turned out that I didn't have any. What I did manage to use instead was this metal tube - it was scrap from an old side table.
Cutting apart the tube was substantially trickier than PVC would've been though. The ends were cut off with a hacksaw, and the middle 'window' section where the can would be loaded was done with a Dremel, a file, and a lot of patience.
The two plugs that would form each end were cut from a scrap of kitchen counter top, cut by bandsaw and trimmed to create a tight fit for the base end, and slightly looser for the plunger end.
Initial testing showed the wood wasn't quite strong enough on it's own and started to crack, so I took the whole thing apart and reinforced all the joints with metal u-channel.
In the end, the design works, but it's a lot bulkier than I'd originally hoped, and would be best suited to perhaps being mounted next to a recycling bin, or maybe a can vending machine - as the test video below shows, it's a bit wobbly when just free-standing.