Any chainless bikes in US
I am guessing you're thinking of similar shaft-driven bicycles when you say "chainless", and those are indeed rare (although CeramicSpeed is working on a shaft-driven concept).  However, if you're looking for anything that doesn't have a chain, belt drive bikes are by far the most popular option, and are widely available from many different manufacturers including Specialized, Cannondale, and (previously, at least) Trek.  Ask at your local bike shop and the odds are very high that they'll either have at least one belt drive option in stock or will be able to order one for you fairly easily.