As has been mentioned above I am in the process of building a demo bike for the shop around a Pinion gearbox having completed a frame with one for the Bespoked Bristol Show earlier in the year. Pictures of the first one are on our Flickr page here and here.
I must confess that despite being a big fan of 'gears in a box', we don't have a final solution yet. BUT the Pinion is a lot closer than anyone else has got before. The gear range may be wider than a lot of people need, but it wouldn't be any lighter if it had a narrower range. The bike ends up very balanced as the weight is central and low, you end up with a strong rear wheel and (on a hardtail) no issues with the chain coming off. We are still working on a full suspension design and this will be made Pinion compatible by using their tensioner which mounts to the gearbox rather than a mech hanger so you still get very good ground clearance.
I'm not sure if the red and black bike's owner using Singletrack but I'll see if I can prod him for a bit of real world feedback. His bike ended up about 32lbs but we are hoping our demo bike will end up a touch lighter (hopefully sub 30) without going too crazy as we should save a bit in the frame as well as the build.
If anyone has any questions feel free to email email@example.com or call the shop on 01433 621111. We will update the website/twitter/facebook when the demo bike is complete