Note: much is always made of the suposed inefficiencies of internal hub gears, but the Capreo's 9, 10, 11 and 13T sprockets can be less efficient than a good IG. (The chain links have to rotate through relatively large angles
under load.) See the report beginning on page three of:
http://www.ihpva.org/pubs/HP52.pdf
TCS
There are a few discussions regarding internal hubs versus derailer equipped bikes.
http://www.bikefriday.com/node/678
http://www.bikefriday.com/gearing
The Bike Friday links above discuss the capreo hub in depth.