Update! First hinge and Front I/O prototype.
I got a package from shapeways today. The final result first:See it in action here
As you can see, the hinge works pretty much flawlessly, there's very little play in it. This solution for Front I/O is the easiest and cheapest one to manufacture and it's the minimum base option that I can guarantee will be offered. More complex I/O or upgrades (more USB ports, audio, USB C-Type, etc.) will probably be implemented as stretch goals.
That way the savings made on the metal parts from selling more units actually benefit the consumer and don't just result in me getting a higher margin, which seems like a fair way of doing things.
Now for a few more details. This is how the hinge arrived:
The two pieces are connected to reduce cost. Having a single piece is easier to handle for the manufacturer than having multiple pieces that need to be searched for in the big pile the printer creates.
First step is to break the studs off, which works very nicely.
Then insert the nuts into the holes. Those will be used to mount the hinge to the frame. Nuts are more durable and precise than printed threads or self-tapping screws.
And finally, a small metal rod is inserted into the base of the hinge, the moving part is aligned and the rod is pressed through to make the hinge you saw above. The two hooks keep the rod in place to give the hinge a sturdy feel. If it could move around the hinge might feel cheap.
The USB ports are actually mounted with self-tapping screws, but as they won't be replaced, I'm not concerned about the thread wearing out.
As stated previously, STL files and ISO-numbers for all parts will be publicised to allow builders to make custom front-I/O and get cheap replacement parts no matter where they are in the world. It also has the benefit of massively increasing the lifetime of the case. You'll be able to replace any of those parts even in 10 years if you need to.
I'm not sure about what license to use for the STL parts, if anyone has suggestions, please let me know.