Although this thread is two years old, I really wanted to thank @Selander for his great ideas for motorization with the L-Motor. I am using a variant of concept #1 to motorize the prison car of the Constitution Train Set.
The battery goes into the (slightly) modified tender. The prison car had to loose the prison door inside and also the lever that made the door with ramp at the end pop off (that door is fixed now).
As @Selander writes the speed is decent but not very fast, maybe half of that of the PF train motor. Torque is plenty and traction seems fine, the prison car easily pushes the whole train around the tracks.
