Update: After I moved on from my bread machine roaster I no longer had a use for this cooler and it went into the scrap pile.  It worked really well though!

My bean cooler uses a squirrel cage fan mounted to the underside of a wooden box.  After the roast I dump the beans into a wire mesh colander which is then put into the hole in the top of the box.  Fan goes on, and the cooling commences.

Here’s a video of the thing in action: