[wrxtasy]

I just use an old iPhone or iPad USB charger and a HardKernel USB-DC Plug Cable, although a USB2.0-OTG cable works just as well.

You can get a power supply, and an Oz adapter but its not really needed as AML boards draw far less power than the RPi ones.
Even if you were adding a 2.5" USB HDD, I would still not trust a power supply to give you reliability and use a powered USB hub instead.

VC-1 content playback still has some minor stuttering issues on AML S905's

I think that's a bit of an understatement. Interlaced VC-1 is currently very broken, not just minor stuttering. 1080/59.94i (aka 1080i29.97) is unwatchable. (Interlaced VC-1 is also very broken on Linux Intel systems, though fine on Intel under Windows, and also fine on the Raspberry Pi, with a couple of exceptions that are being investigated)

I'm testing out samples from here:
http://kodi.wiki/view/Samples

Then I have other clips that play perfectly fine, so yes VC-1 (inc WMV3) is still a WIP.
Thank goodness Interlaced VC-1 is pretty rare.