My main machine is a Bridgestone Albelt I found at a local Japan surplus store. They've been in production for a couple of decades but are rarely seen outside Japan.
Belt drive isn't anything new.
The problem is outside of Japan you can't just bop down to the local bike store and pick up a replacement belt or cogs to get a better gear range. So I got a second Bridgestone with a conventional chain to experiment with different sprockets and have something to ride while working on the other.
My R&D machine.