two USB ports

I don't know if both could provide the same amount of power, and I'd bet -- given that laptops don't -- that the phone would only be able to charge off one.

USB ports aren't perfectly interchangeable today. If they can't be made to be, I kind of wish that at least USB would have a set of standards for indicating power-in capable ports and ports by wattage capability. Like, reserve one color or symbol or something for one, one for another. Right now, device manufacturers just do whatever and sometimes don't indicate what is what. I mean, yeah, it's great that they're backwards compatible, but when you have ports that don't all behave the same, it'd be nice for it to be immediately-obvious what they do.

Also, while I'm dreaming, I'd like power-pack and battery capacity to be listed in watt-hours rather than amp-hours, given (a) that voltage isn't universally the same and (b) that what people care about is about how long something can be run ("I have an N watt device and an M watt-hour battery...").

I'm pretty sure that a USB hub would work at least on Android, giving you as many ports as you want.