The CRJ does have crew closets. There's a FA baggage closet immediately below the forward cabin interphone. There's a cockpit crew closet (big enough to hold two PNT bags) up front behind the galley. (It's the bi-fold door that's below where the FA jumpseat plugs into the wall)
Unfortunately, after 9/11 the mandate for new cockpit doors resulted in the cockpit crew closet being rendered useless for everything but thin laptop bags.