Advice on a Wild Idea

Since tracks are nowhere close to me and not to mention expensive, most of the time the only place I throw a leg over the bike is on race day, I've been thinking awhile now about trying to replicate holding on to bucking handlebars to train and help with arm pump without actually being on the bike. I figure if I could find something that vibrates/bucks around like actually racing, that I could attach handlebars to it and just hold on to train for the dreaded arm pump. Now before you all comment on other ways to help with arm pump I know its mostly cardiovascular and I train/workout accordingly, but I thought it'd be a really good way to condition the arms and muscles. The only issue with this is I can't think of anything that would replicate this movement and vibrations besides maybe a lawnmower but that'd be rather impractical and only simulate the vibrations, if anyone can think of any ideas I'm all ears, thanks.