What keeps you from having it open source and still sell assembled boards? I truly believe 90% of the audience would buy it pre-made from you, if the price in resonable. Ordering a pcb, all components and then soldering it is quite a barrier for "ordinary" people.
You will also be able to receive bug fixed/pull requests from other community members if you keep your project on github/openhardware.io.
Here's an example for the MySensors Micro: https://github.com/mysensors/SensebenderMicro/pulls?q=is%3Apr+is%3Aclosed