I recently did some looking in regards to 118mm ISIS Bottom Brackets. There are several available.
From reading posts about the added loads on the stoker BB, I tried to find something with added bearings.
Many BB's had three bearings, two on the right side and one on the left. This didn't sound great for the stokers BB
In the end I bought two Truvative 4 bearing BB's, 118mm long. I forget but believe they were a Downhill part. The units do have sealed bearings that with some light hydraulic press work should come off the axle.
Upon installation, I followed their directions, torquing each side. By design, the right side cup is secure, bottoming and tightening against the frame or eccentric. The left cup was torqued against the BB spacer housing. This method made the BB's somewhat binding. Because our frame uses a 68mm shell, and these were 68 or 73, with the clearance filled on the right with an aluminum spacer, and on the left an "O"ring, I made a change.
I removed the left side "O"ring, went by the shop and picked up two old school BB lock rings. These replaced the "O"ring and allowed me to properly torque the right side cup, and then tighten the left cup until it lightly seated on the BB spacer housing, then locked the cup with the lock ring.
No axial play, and spinning free, maybe not as free as a real high end BB or worthy of the OP's Calfee, but worlds better than how it was designed.
Chain alignment was good with our triple setup.
PK