Let the hive mind of Engadget get that for you.
"I am looking for a device that will stream sound from one source to several recipients. For example, I want to stream sound from my TV or stereo to my phone or MP3 player that has radio and Bluetooth capabilities. I have looked into radio transmitters and they seem like a decent choice, but I can't find one that uses external power (USB or from the plug) and I would want one with a transmit range of around 50 meters. Thanks!"
"The researchers also learned that the self-powering backpack weighs only slightly more than a conventional pack—equivalent to carrying around an extra candy bar."
so there you have it. the entire power generating contraption adds hardly any weight to the backpack so if this backpack allows me to bring only two high power battery packs with me instead of five to keep my gadgets running during a long hike I'd GLADLY wear it.
Besides, judging from the video of the guy wearing this backpack this backpack looked extremely comfortable to wear.
There was some movement when he walked but when he was running there was hardly ANY movement on the pack at all! Anyone here that has actually jogged with a 60+ pounds heavy backpack will tell you that that it is a pain to do, no matter how hard and tight you strap the pack down it will move around so why not put that movement into good use and get added comfort as a bonus?
This backpack must be a dream to wear, and anyone else objecting to it should be shot..