Both my wife and I train and race with power on our single bikes. We considered the Ibike a couple of years ago and passed. We use both the Quarq Cinqo and PowerTap with a Garmin 705. I thought about using the Ibike for the tandem. Since we have not been riding the tandem much this summer it fell off the radar screen. I think everyone is familiar with Ibike's shortcomings. I can see how it could be of some value on the tandem. Speaking for myself, once you train with power, one gets good at estimating power based upon perceived effort. Obviously, not very accurate and on a tandem there are two people coordinating their effort. I can see how an Ibike feeding both Garmin 705s could add some value.

There is a new power meter coming out next year. Here are some details.

"Clark Foy of San Jose Bike Club has invented a new powermeter. It's
a bunch of accelerometers, stuffed into the hollow pedal spindle of a
Speedplay pedal. Not only does it yield power information measured
directly, it also measures left/right, and in each of the pedal circle
quadrants, so that feedback can be incorporated to improve
efficiency. It's wireless, and communicates to existing "head" units
which use the ANT protocol, which most use. Garmin is one such unit;
there are close to 10 brands that could work.

There are computer chips inside which are electrically reprogrammable,
so as the algorithms improve, the pedals can get "software upgraded".

Retail price will be something like $899, which includes the pedals
($200 retail price). You'll need to purchase one of the head units
separately, like a Garmin.

Product will be launched at Interbike, early production late Q4'09,
broader distribution in Q1'10."

This looks interesting for the tandem. When I first heard about this, I thought tandem and track. Speedplays are fine for tandem but I would not use them on the track.

I can see it now. Go out for a tandem ride and then download the individual power data to Training Peaks and let the discussion begin.