Are you reasonably handy with tools and willing to experiment? Do you have a regular bass drum pedal and a beater you can sacrifice?
If so, I recommend getting some various pieces-parts and building your own version of an inverted bass drum trigger, like the Roland KD7.
I envision an L-shaped bracket of thick steel, maybe an inch or inch-and-a-half wide both ways and 6" long, with a 6" piece of 2" PVC screwed to it. (You can also use a 6" length of drum rack tubing). Clamp your pedal onto the L-bracket. Put your beater in the pedal upside-down and bend your beater shaft so the head hits the pipe, and enclose a piezo transducer inside tightly packed with some sort of foam. Get end caps for the pipe, and drill one to accept a 1/4" jack. Solder to piezo to the jack, screw-and-glue, and put something softer and quieter on the striking surface... neoprene, rubber, etc. A piece of mouse pad (yes, from your computer) works great for this. There you go! I am guessing you could do this in an afternoon for $20.
2 end caps
Black spray paint?