Somebody went to a lot of trouble to mate all that stuff together. The backing plate is from a '63-72 Big Twin, and I think the drum is too, but it looks like it's been converted to bolt on to whatever that hub is with 6 bolts, rather than the normal 5. Without taking it apart, there's no way of knowing whether the drum could be bolted to the hub for which it was originally intended.
But that hub is pretty cool. The whole setup is. Putting it in a round swingarm, you may have to machine up an axle and spacers. Then the big IF is, with the tire centered, would the sprockets line up?
I'm lost on a price, though. No more than the unmodified parts would be worth separately. Anybody that does that kind of work is aware going in that they'll never get what their time and effort is worth back out of it. And if they're not aware, you can't afford it.