It’s apparently trickier than just shorting the data pins—I read somewhere that the Apple devices put different voltages on each of the data pins, depending.
I got a better response from Limefuel:
Chris: “Okay, so if I were to hook this up to a simple 5V 2A ‘lightbulb,’
there’s nothing in the battery that limits the current flow. This is
opposed to ‘smart’ batteries that limit the current flow to 1A unless it
successfully negotiates a handshake with a device that says something to the effect of ‘I’m an iPad, please give me 2A.’”
Limefuel: “Our batteries are not ‘smart’. There is no microprocessor or the like that would exchange data to make the ‘handshake’. The battery will only limit current flow in the case of overheating, otherwise, current is controlled by the device that is plugged in.”
So, there you have it. We’ll probably only know with an order and test, but I think we have strong contender for wearable batteries. 
+Randal B, what brightness were you running your leds at?
I just got an authoritative answer back from Anker tech support, all their batteries supply 3A max over both ports. So the Limefuel still looks like the way to go.
Cool. I can confirm that the LimeFuel batteries did fine with my jacket. They had about 100 LEDs connected to one, and 50 LEDs + RaspberryPi connected to the other. Lasted at least a few hours running my program at full brightness (probably 25% overall?).
Oh Jesus. I’m gonna have three times that, I need more than a couple of hours! :-/
Yeah, I haven’t done any “scientific” testing. It would be better to set the LEDs to 50% white and see how long they run, but haven’t gotten around to that yet. Not sure I’ll have time before the Burn. Anyone have time to do so?