I've been loving my do-all bike, two months into service. Singular Gryphon frame. The Nuvinci has been very nice thus far - super smooth, and no sense of inefficiency to these legs.
The frame is very similar to the Salsa Fargo, but has an eccentric BB, which makes the IGH a cinch.
the 32x18 gearing gives a range of mid 20's to about 90 gear inches with my 28x50 Marathon Supremes (622 bead).
I built this bike as a commuter and gravel grinder/bikepacking rig. I look forward to taking it offroad, and have a set of 29x2.4 Maxxis Ardents ready for action. I can remove the rack and fenders in 5 minutes, and have the bike ready for singletrack in under 30 minutes.
Here it is in its 29er offroad guise. About 30 minutes or so for full conversion from commuter mode.