Started looking into activation devices. Ouch, it does not pay to be disabled. This switch cost $101 USD at the time of this writing (and that they indicate is with a 30% discount:
The nice thing about this switch is that it has a 3.5mm plug:
Switch size: 1½"L x ¼"D. Cord length: 6 feet. Plug: 3.5 mm. Weight: 2 oz.