the doorbell button would be easy to incorporate into a handheld buzzer. you could get a piece of PVC pipe..maybe 6" long, i'm not sure what size, perhaps 1.5", slide a standard happ pusbutton into the end that is wired up to the doorbell button pcb, which should easily slide the pipe as well... you may need to wrap the threads of the buton with electrical tape a few times to make it fit snugly inside the pipe.