I'm probably going to convert this 18" Prairie Breaker II to single speed. Add some aluminum XR50 bars and a layback seatpost.
I wouldn't mind a coaster hub. But that's an additional cost and I don't want to relace the rear wheel.
But I might not do it if I had to use a tensioner.
I got a similar 17" Raleigh M-40 that doesn't have adjustable dropouts and it will get a direct drive 32cc weedeater motor instead. It will reside at work.
Here's my old Schwinn Suburban that I stuck a Nexus 8 wheelset on. Deraileurs were kinda jacked up and I wanted to see how it looked with all that mess removed.
I thought it made the bike look way cleaner.
But it just didn't fit what I wanted. Too tall and bent over.
That hub, along with the Suburban's front sprocket and crank will go on my 26" cruiser/klunker build instead.