Just to go with your idea, lets say we do this, then another team signs him on our behalf, and them trades him back to us a year later for some nice added benefits.
Is that really worth it for us? Give up about a 1st round pick to save .5M -1 M cap hit over a couple years, not to mention any additional assets we might have to give up if the league cracks down on this move.
EVEN if there were no rule against it. I could easily see it going down where the player just signs a massive deal somewhere else.
What would the Leafs do? Complain about it? Oh hey! Commissioner! We were trying to circumvent the cap by making backroom deals that the league wouldn't approve of, and the other party didn't hold up their end of the bargain! .... The player could just pretend it was a legitimate buyout because it was a bad fit, and then go sign a huge contract, and there's nothing the Leafs could say about it.