Recomendation for IC to build iphone battery pack

What I want to do is build my own iPhone power source, I just want a universal USB out, so 5V up to what, 800mA? I considered building this with a large prismatic lipo cell, but then I would need a boost circuit. Blech. Or, I wanted something I could connect to a RC lipo pack, or like the one posted by Kospap here: http://www.candlepowerforums.com/vb...d-Batteries-in-parallel&p=3750345#post3750345 4 18650, either 2S2P or 4S. Of course, for efficiency I don't want to use a linear regulator to do it. While a built in charge controller would be nice, I wouldn't be completely adverse to using my hobby charger, if need be. I just want a decent amount of watt hours, maybe 3 times that of the iPhone battery, or better.

I suppose these may exist already, but seems I could do it with what I have on hand mostly, since I am a flashaholic and not just an ordinary citizen

As a Flashaholic, you would surely go for one of these Power packs - with White and UV light built in

http://www.dealextreme.com/p/2400ma...light-money-detector-cellphone-adapters-73078

I use something that looks just like this to charge my phone or Ipod from a 18650.

http://www.ebay.com/itm/USB-Output-...473?pt=LH_DefaultDomain_0&hash=item2a127c6841

however, the one I got from Ebay looks a little different than this one and is no longer listed from the seller I bought it from (he sells mini stereo amplifiers). Also it had a tiny blue led to indicate charging and required a 470k-ohm resistor placed between the + output and both data pins (center) to charge the Ipod. I would imagine this would be the same for an Iphone. I haven't tested it on a Iphone yet but it recharged my friends' Blackberry and Android. It recharged my Motorola phone with or without the resistor.

Also, it does not have reverse polarity protection which I learned the hard way (fried the diode) and had to order another.