I recently finished work on a wheelchair for Stan the tortoise. Stan's front right leg was injured and he needed a sturdy wheelchair while recovering. My design features adjustable straps, foam pads to grip his shell, and wheels with bearings so he can easily scoot around.
This is the most recent iteration of the Klann linkage crab robot. It is remote-controlled and is able to move around pretty quickly. I recently took it to a local beach for an extended sand walking test, it worked great!