So how much power is "enough" power? ;p But I don't think it's a good idea to take it though security. They might mistaken it for a bomb or something else dangerous and it could get you into trouble. I would imagine it would be putting a lot of stress on the iPod dock connector too, due to all that weight. If it was me, I'd remove the dock connector and put a USB port on it so I can use it to charge any USB device. I have one of those with just a USB port on it and I like that design better. I need to figure out how to make a USB and Line Out combo cord for my iPod though, because the headphone jack is broken on mine and I have to use a Apple dock to Line Out cable and a portable headphone amp to hear it. It get's annoying charging OR listening to it when I want to do both.

I thought about doing the USB connector idea, but after some investigation online I found out that iPhone and iPod need a reference voltage on 2 of the 4 pins. I don't have a way to replicate that in a way that it keeps charging even as the reference voltage changes from low batteries. I did however make a portable charger that only has a USB port in it and is charged using my heavy duty lipo charger, but it's a bit impractical to use in a public setting. I can use it to charge stuff, but when I need to charge it I need to bring a bag of power supplies and large cables to run the charger. I don't think it would be too hard to make that kind of cable. If you know how to solder you can probably make one pretty easily.

Oh yeah, I forgot about the reference voltage. My older 30GB iPod Video (which I no longer have) worked without the reference voltage, but my latest gen 160GB iPod classic doesn't. That USB charger doesn't sound too practical at all. Plus you'd probably would get some strange looks when you pull out a bag of power supplies and cords. I did find the pinout for the dock connector and I do know how to make one of those USB/Line Out cables, it's just that I don't have the proper/all the tools necessary to make one right now and the already made ones are either too expensive or really low quality and breaks very quickly on me.