The trash can lids are really closer to a drop-out chamber than a cyclone. They've been mis-named for marketing purposes.

It's pretty easy to make a small cyclone using standard 26-guage HVAC parts; a small chunk of 8" duct, an 8-5 reducer for the bottom, and a plywood top with a 3" outlet tube. The only trick would be to cut a tangential inlet into the top of the 8" piece. The fan would have to be either outlet mounted or seperately mounted. If you mounted it seperate, then you could set the whole thing on a bucket for a dust bin. Or the parts are probably available in plastic. You could even make one in wood if you wanted to spend the time.

Cyclones work pretty well down to about 100 microns, and drop off rapidly below that. You have to filter the air, preferrably HEPA stage, if you want to recirculate it.
: Sounds interesting--how do you do that?

: Shawn