Rohloff and Pinion publish that kind of data... But that is in laboratory clean conditions... Mike Burrows has written about it as well...
Mtbing however has mud sand and leaves... So the derilleur only beats a hub gear or gearbox in dry summer conditions.
Hub gears are not the best around trails the weight needs to be central
The other 9 months are where the gearbox is King

Thanks Tortoise and Bakerjw... There are too many companies out there where the bosses do not ride and have lost touch.  Too many companies run strategically on marketing campaigns.  I have worked on some cool stuff and some bad.  I have tried to think of all scenarios of how I ride and how others will use this bike.  I hope to be able to grow this and sell a few frames so that I can develop some new stuff.

I was riding 7-8000 miles offroad per year on my offroad mtb commute (very very lucky location).  Obviously I had some serious component failures.
This lead me to ditch the derailleur and chain. 
I developed a belt tensioning system that had a wide band of ratios to select Gates 39T : 20-24T giving me 2:1 to 1:1.6 ratios.
At the same time I knew the Singlespeed market was limited and was looking at developing a frame around hub gears and gearboxes.  I will be blogging about weight in the next few weeks, but this is a snap shot of my usual rant.... 
We think nothing of carrying 2-3Kg of water and carry most of that around for more than a few hours.
A 700ml water bottle weighs 0.7Kg
We are selecting wider and wider tyres for comfort and grip.
We load our bikes with stoves food and fuel.
Still we complain about bike build weight.
At the end of the day static weight is not as noticeable as rotational weight.
Derailleurs always have the potential to fail and do not survive Winters (esp British ).
I have developed my frame around the Pinion Gearbox because I have tested it in anger and think there is room in the MTB market for alternatives to the derailleur.  I know it won't appeal to every body, but the Pinion Gearbox is here and some designers have to take up the challenge.

They aren't making the gearbox, just speccing a frame from China.

Hello - I am Steven Olsen the designer and owner of Olsen Bicycles.  I have spent a lot of time designing this in the UK to get a low-maintenance MTB.  Just a correction to Tortoise.  My frames are NOT specified from China - they are hand build in Sussex in the UK.  I have a block tool for this frame and am Kickstarting the idea to give the first customers a deal and also to get a minimum run so that I can order all of the stainless fixing points.

I am a small business not a multi national and want to manufacture in the UK where I can control the quality of every frame.  I have been in the bike business for over 5 years, working for others to transfer production to Asia.  If you are interested you can look at my development on my website www.olsenbicycles.com

I am have been aware of Pinion for sometime, so developed a 27.5+/29" frame around the gearbox for #greatbritishweather trail conditions :-)
I have had Rohloff Speedhub as well, but for this frame the Pinion gearbox has the most advantages.