2Fast...tired of planes?
There are other OB Mfg (Thunder Tiger, OS), but finding a distributor stateside is getting difficult. But don't let that keep you from getting into a boat. Several companies make power heads (CMB, Mac, Nova Rossi) and others produce their own lowers (Lawless, Hyperformance).
The market is there...it's just a matter of time before someone steps up to the plate to fill the void left by K&B. Plus, eBay is full of K&B engines and parts.
Then you have the world of inboards (cats, riggers, v hulls, etc). You can have gas powered or electric. Big, little, scale, inexpensive and not-so-inexpensive, kits, RTR, and on and on...
Jump in, Dude! We're here to help!