I must say: I wasn't interested in joining or starting a company (no clue how my employer would feel about that!). For a software project, this is strictly not necessary, just define a license for what you publish and keep track of who owns copyright to what.

I see the point for a hardware development: the prototypes are expensive, and you only get good prices if you pool many orders. For my own part: I just want to get a workable design and possibly not have to sell organs to pay for a small number of boards  

For the purposes of the development effort, these are two separate issues, though: we can assign a license to the designs without having to go to the hassle of incorporating ourselves. The prototypes may even be doable by enthusiasts with deeper pockets than the rest. The mass order requires a company. That needs not be founded by us, though: Seeed Studio is for this sort of thing.

As for license preferences: I would be happy with many of the OSI approved licenses, but GPLv3+ or maybe GPLv2+ would be my preferences.