So I made one using one of his favourite chocolates: M & M's.
The cake, of course, was Husband's preferred flavour of choice: Chocolate with chocolate chips (because chocolate by itself is too boring, apparently). When I'd almost reached the top of the chopstick with the M & M's, I attached the box onto the chopstick with some melted chocolate. It took a few goes to actually make it stick properly, so eventually I used a peg to hold it in place, and sat it in the fridge to set quicker.
Due to things out of our control, though, we didn't get to eat it until the day after his birthday. But here he is - my wonderful Husband, holding his birthday cake, on our way to our neighbours & good friends' house (who have air conditioning!), for the official birthday cake cutting celebrations :)