I've seen many versions of the home made charcoal canister. Some use an aluminum water bottle, others a length of PVC pipe and one person even made one from a pop-up lawn sprinkler case that already had a 1/2" NPT in the bottom. The canister may be the best answer. Some people question why the charcoal doesn't get saturated with fumes, when the cars sit idle for a long time and are often driven few miles. Driving would help purge the canister, as some air flows through it. From what I've read, modern cars have a vent valve off the canister that stays open when the car is not running. It's only close during the purge cycle. The purge valve allows vacuum to suck the fumes from the canister, but the vent valve must be closed, or it would create a big vacuum leak at the engine.

Hot rods by Dean sells the $250 canister. No sense in that, when it's hidden.