Bike porn

I looked at Old Faithful for comparison, there isn't much similarity apart from the single main beam, and Obree's was considerable larger. Going from 30mm to 40mm on the main tube OD can get you twice the torsional stiffness at the same weight, and Obree's was also straight and more robustly gusseted to the seat tube.

I was reading an article about a chap that had recently made his own home-brew bike and had a couple of features in homage to old faithful.. Now if only I can remember where I saw it.