That's a great idea!! He'd be perfect for it- he never goes to the bathroom outside his stall xD Not sure why - I think he's modest. I've started teaching him some simple tricks like targeting and verbal commands to move around.
My concern is that he has a 'criminal record' he attacked a few people in the past, they deserved it, but none-the-less he's labelled a 'liability'. So if he ever hurt anyone he doesn't fall under the label of 'horses are unpredictable and can be dangerous so you can't sue me' sort of thing, because he's proven he is dangerous. So I don't know if I could do that - but I'd love to!!