Work- around or a "special" controler?

Hello all,
my preffered work flow for finding a melody is to repeat the drum or bas track along 2 or 4 bars and to try a couple of times to get a good melody on another track.
Could someone give my an ideea how could I clear the melody track and repeat the melody only with a single button?
Does exist a midi controler with such a function?
Otherwise I have to click the melody track, to clear the field and to restart.
Thanks for any ideea.