I was in a jewelry store this weekend and came across this. Anyone ever see one of these?

Yes, they were bought by some performance boaters in Sweden and probably Norway too about 15 years ago. They cost $3k-$4k then. Width only 45mm, but I find it sporty looking in a good way due to the materials used.

Did KOENIGSEGG build the engines or were they just a sponsor?

The driver, owner, and manufacturer of the Hydrolift "Spirit of Norway" boat, Bård Eker, was part owner of Koenigsegg in those days and therefore the marketing of the cars on the boat. He became the 2005 Class 1 World champions in this boat and the same year his Hydrolift factory burned down. It was very tragic, but he built it back up and it's a state-of-the-art industrial design and manufacturing complex now. Here's a video of the boat from the following 2006 season, now with Steve Curtis on the throttles and Norwegian Bjorn Gjelsten driving.