The ICE40 is about as close to this as you can get. A lot of open source tools work with them, and you can find boards being sold by companies that generally specialise in the Arduino ecosystem. Unfortunately not open hardware, but that's unlikely to happen anytime soon.
You'd never want to build anything production-quality with one, but they're decent enough for hobbyists.
You'd never want to build anything production-quality with one, but they're decent enough for hobbyists.