I dont know anything about sleds, but it seems by first glance to be the best donor, if not some sort of ATV 2 stroke twin.
But maybe the powerband of a sled will not suit the powerband to keep the jet pump efficient ? Ive tried to find som hard data and content about efficiency of smaller jet pumps (jetski size, not later vessel size). But the sweet spot seems to be around 7000- maybe 8000rpm.
There is a Finnish guy who has some sort of Frankenstein engine in his AM hull, either a Sled block or jetski block, but with fuel injection from a sled.
But defiantly a very interesting project!