I'm curious what he wanted to do with it too. At times, it could be handy to have one that worked on your bike pack voltage.
So a 48v dc to 120v AC inverter could do something handy, like run standard AC chargers for other devices, Phone or ipod, maybe a small cordless power tool. But you'd have to have a huge battery to do much with it, so I don't see a ton of use for it.
Mostly handy in a power outage, so you could keep the phone working, recharge some flashlights, that sort of thing.
My power outages are so regularly scheduled, I have two generators.