Coolest.
Suicide.
Ever.
My brother (who at 6/4", 300lbs has an affinity for all things oversized, overpowered, and overly loud) test drove one many years back. He said the weight was there, but all felt like it was sitting very low on the frame. He likened it to riding a Weeble.
Triumph do a 2.3 litre inline (fore-and-aft) triple that is supposedly some flavour of rideable. 
That Triumph rides well, you’d be surprised at how well it gets around corners, its no supersport but still, you’d not expect it go so well in the little lanes.
It also takes to tuning quite well, it can be fitted with a very naughty supercharger
In stock form it can get up to 60mph before a CBR600.
You think the Boss Hoss is overkill, then check out the Dodge Tomahawk.
It comes with a 500 HP. 8.2 Liter V-10 engine out of the Dodge Viper sports car.
It appears to have 4 wheels. Doesn’t that make it not a motorcycle by definition?
Yes, the Tomahawk is not a motorcycle; it’s not street legal at all, either. Also, although there’s footage of someone riding it, I can’t figure out how one steers it.
However, for a real motorcycle in the same league, Boss Hoss has also used that engine:
Oh good grief.
In my book if you sit on it and not in it and you lean it to steer,it"s a motorcycle.
Peace
If it has four wheels you don’t lean it to steer.
If it has the right sort of suspension you might. I’ve seen prototypes (in person, not internet mock ups) for hybrid car/motorcycles (One in particular was actually a hybrid, in fact. Earth Day brings out the really impractical ideas in people.) with three or four wheels. They lean to steer and have a tricky suspension where the body leans over and all the wheels remain in contact with the road, just tilted over.
Isn’t that thing the Batcycle from Dark Knight?
Here is the wikipeda page for the tomahawk that describes how the suspension works.
(Bolding Mine)
Peace
So, do you get an International CXT to haul your Boss Hoss around in?
Those things still around? The link was to a 2005 story.
I caution people who are buying their first motorcycle to avoid getting too much bike. Thanks to that bike, no matter how experienced, big, and strong a rider may be it will always be possible to get too much bike.
In the last year, I’ve stopped to help 3 or 4 guys who dropped a motorcycle and weren’t able to get it back upright alone. My guess is that they were just barely able to keep it upright, especially when riding with a passenger. The American affiinity for bigger and more powerful backfires pretty easily when we’re talking about motorcycles or guns.
I believe so. A friend recently saw one stopped in a Florida gas station. It was being driven by a huge and friendly guy who proved to be Shaquille O’Neal.