I wanted to add a new switch to my system, but wanted something that felt better under my foot, especially for tap tempo. Knowing that I needed a unlatched footswitch I looked to my keyboard sustain pedal. Tried it out and it works great. Is the perfect size I was looking for and feels great under foot for tap tempo.
The one I use is the m-audio sp2. http://www.m-audio.ca/products/view/sp-2
Hope this helps someone.