Not to leave the 2 wheelers out of the collection, here are some chain lines of two wheel recumbents.
Says Bruce: Stephen (tennbent) and I wanted to eliminate the inherent problems on his Optima Baron that also exist with the chainlines on a lot of mid and low racers. The picture above shows the chain crossover between idlers.
The picture above shows the revised chainline, with crossover issue resolved. First, we wanted to clear the front tire/fork, and also to eliminate any chain cross-overs. We also did some other minor chainline mods to clean up the line. I won’t go into all of the details of HOW we did this, but the pics show the results. And, it works quite well. Stephen says it quieted the whole chainline a lot.
Admittedly, the change added another small bend in the power chain line, which technically adds pedal effort, but Stephen says he can’t feel any extra effort, and most folks won’t either. Maybe Lance Armstrong could feel it. The extra bend is about what most trikes experience in chain line bend. Bruce