My next pet would be a Wildcat except for two things: 1) they are not available to consumers and 2) it appears to run on a highly polluting engine. (See the clouds of exhaust when the engine is started.)
Another video of the Wildcat (which shows as an option when the above video finishes) shows how it could be used to assist those with disabilities. Well...they don't really show that; but, I can infer from the way it performs on hills that it could be really, really useful in the "assist" role.
__________________* IEEE = Institute of Electrical and Electronics Engineers - to which Hunky Husband belongs. Years ago, I belonged to the forerunners, IRE (Institute of Radio Engineers) and AIEE (American Institute of Electrical Engineers).