Bike chains come in different widths between the side plates to accommodate denser drivetrains, but the pitch is 1/2". Earlier chains were 1" pitch. I don't know where you'd get an industrial substitute for 1/2", but conveyer belt companies make block chain that's very close to early 1" chain, however it's likely more expensive and has greater friction and I don't know why one would use the archaic 1" unless it was original to the bike or they really wanted it to look like it was built a long time ago to the few people who'd even notice. IMO, you would want to use all bicycle parts for cost, availability, and servicing. The main concern you'll have with compatibility is width of the chainrings and sprockets matching the chain. Single speed chain is wider and the gears it fits are wider. As you increase rear cassette width, the chains get narrower and more flexible. You can use thinner gears with wider chain, but it may make more noise and, if using a standard cassette (say a 9-speed), the wider chain might be too wide to fit between the gears. You can fit a wider gear with a narrower chain if you REALLY want to, but it would require narrowing all the teeth with a grinder or something and that's a hardened metal, so I would just try to keep compatibility matching.
Beyond this, though, I'm not sure what your plans are, but the few things I can think of would use all off the shelf bicycle parts. If you look at tadpole recumbent trikes, they sit low, but are RWD and the chain passes under the low seat. Bicycle chains can be connected to whatever length you want, so there's no need to look for something obscure. If you're planning on a super lowrider seat height and want to run a jackshaft to transfer power from a centered chainline to an outward one, you could still use all bicycle parts. I would want the jackshaft supported at both ends, so you'll need some kind of frame extension at least on the drive side, but two rear hubs—one at each end of the jackshaft—could be configured however you want, be it single speeds or multi on either end or both and centerline and outerline chains wouldn't even have to match width. Say you wanted your shifting done on the centerline, you could use single speed chain parts to transmit drive at the outerline and run whatever configuration on the centerline you wanted. The only question there is jackshaft compatibility, but 10mm is common enough that it shouldn't be too difficult to match.
