Hi,
I used this one on one of my builds (sorry.. the page is in German..). It's tiny, but works great:
brake/reverse-switch
They have a new model that includes a beeper now..
Beeper thingie
Here's the vid of it in my Jero:
(I used the reverse module in combination with this module here:
turn signals and lights
..this one switches turn signals and lights).
Cheers
Pip