I have no direct experience with the ibike system, however there was a fairly extended discussion on slowtwitch.com
http://forum.slowtwitch.com/gforum.c...;so=ASC;mh=25;
I have however, I think, that my lab and I are the first to have successfully measured the overall power and power of the captain and stoker independently. We did laboratory and on-road testing and recently submitted a manuscript to the Journal of Applied Biomechanics. The paper is undergoing review as we speak; I don't expect to hear a decision for a couple months.
Our set-up consisted of a stock Burley Paso Doble, we replaced the standard cranksets with SRM pro versions and had a customized rear wheel built by wheelbuilder.com with a power-tap. The major modification was to remove the timing chain from the left side to the ride side. We used the inner ring of each SRM for the timing chain. This setup essentially changes our 18 speed into a 9 speed but for our purposes it does not cause a problem.
We are using the tandem as a method of "forced-exercise" for Parkinson's patients, hence the need to measure the power of the trainer and patient independently to determine if the exercise needs to be active or passive to lead to improvements in motor function.
PM me and I can send a pic of the bike.
Jay