Camera support product specialists View Factor have used the GoPro Hero to showcase their camera modification skills and created the Novo: a heavily customised Hero 3. The result is a more controllable device, which uses custom geared C-Mount lenses and has a much greater degree of control over all aspects of the camera.
The C-mount system has a back-focus adjustment that allows macro shooting and there's an internal CPU which is interfaced to the camera can disable the standard auto exposure and allow manual adjustment via the lens.
Sadly, this device is not available for sale: it's rental-only from Radient Images.
Apparently, the remodelled Hero 3 takes a lot of work to produce, which suggests that it won't be going into mass-production any time soon, even if it does look like a 100% finished product. But it does, perhaps, show at least one way ahead for this type of camera.