First off, let me say, that this is a great thread. Zap, thanks for starting it.

I agree about not using power from the 770 to get the USB host mode working, as you can't internally limit the amount of current your devices will pull.

For those that don't want to solder internally, although it's really the smart way to go, you could get your hands on an old nokia power tip (an old phone charger, maybe?) and make a little USB-to-Nokia converter. That way, you just need to carry a tip, instead of a whole cable. Yes, again, it's just something to lose/carry, but it's an easy alternative. If I get a chance, I'll make one up, and let you know how it goes.