Maybe a water helmet with GPS built in that beeps when I veer off target on my swim line.

Also something a little older - Biopace

I had an idea for a Timex branded watch to be worn around the forearm rather than wrist that would perform the same function only through vibration or through slight pressure using fingernail sized gps device. It would also let you know if you were properly pacing youself, average speed, etc. It would also use a new technology to tell you your hydration levels letting you know if your in need of water.
But back to the bike idea. i was thinking something a lot different that the current gear driven bikes. My idea would be a fixed elliptical path, and have all the "transmission" bits be held elsewhere, either within the ellipse or in the hub of the rear wheel. Here is a quick example of what im thinking. I am basicly wondering if you think that having a tall elliptical pedaling path would be advantageous instead of a slightly squished circle/ completely circular pedaling path as we see in todays bikes. So your feet actually follow an elliptical path not just driving an elliptical gear.

I don't see how you would have an elliptical pedal path unless you have telescoping cranks or something. An elliptical crank is one thing, but a pedal path would require cranks without a fixed length, which I'm guessing would kill your stiffness and power transfer. Your thoughts?

dont worry about the engineering i have that all thought out, the design wouldnt even involve gears i just want to know if it would be advantageous to have the elliptical pedal path, so you could have a longer pedal stroke and less effort wasted at crank angles where less power can be put to the rear tire. so your leg would be doing more of a vertical motion rather that circular. The idea behind it is that there is less energy being wasted to move the pedals laterally and more of the energy can be used in a vertical motion. By doing this you could also use less of the muscle groups involved in running thereby saving certain muscle groups for the final stage of the Tri. The design is almost fully about rider efficiency, and performance.
I also want to know what specific muscles are most worn out by cycling, and which of those major muscle groups are used in running. I really want to make this more about the Triathlon rather than cycling on its own (You guys and gals, are the masters of endurance and performance). I would rather design a bike that not only helps during the cycling stage, but also by saving certain muscles help you on the running stage.

I would check out the Rotocranks Trisooner mentions. The concept is just as you've mentioned, to give legs the most ergonomical motion. I had Biopace on my bicycle for years, and never really noticed it, until I started riding a lot and trying to go faster - and finding it hard to go fast, not liking it. When I switched away from the Biopace to round, I felt so much smoother, more comfortable, and faster. Of course, Biopace is the opposite of the Rotocranks (the eliplse is oriented horizontally - the idea was to allow momentum to get you through the top/bottom of the ring, though it never really worked, for Shimano or myself). So, the rotocranks may have some mechanical advantage. As far as automatic gearing, I guess it would be a hard sell for racing since the resistance would be fixed, so on days where you're feeling strong, the auto transmission would be holding you back, on days you feel weak, you're not able to spin. If you could adjust the resistance (or desired cadence) on the automatic at will, then maybe that might work. That, however, sounds a lot more complicated and heavier than the simple cog and derailer system on today's bikes. But, for non racing applications, that would be cool (there is such a bike on the market: http://www.landriderbikes.com/features.html), I just don't know how well it works in practice.

Running is primarily dominated by hamstrings, and normally cycling uses a nice mix of hamstrings and quads. To save the hammys, tri bikes give a more agressive position and a steeper seattube angle which forces you to use your quads more and your hamstrings less. I believe that is the type of info you are looking for?

I'm very interested in how this elliptical pedaling motion would work because I can't really picture it without a better explanation.