Awesome info! I'm still not sure how the USB system works entirely, will be something to look into definitely.
For comparison, here's the dmesg from my A43 with a USB hub + keyboard and mouse attached at boot. This is also running 12.04
Edit: Again, but this time with just a USB optical mouse plugged in (one of the old Dell ones)
Looks like it doesn't think it can supply enough power to the device and just shuts off. I know the hardware is capable, I've used the hub, mouse, and keyboard on the OpenAOS kernel just fine plenty of times. It looks like the A43 is only registering a 50mA bus power limit while most devices request 100mA even if they aren't actually using it. I think the hardware is capable of at least 100mA.
Looks like something that is set in archos-usb-musb.c, the value is 50 in the file but the comment says 100. Possibly a scalar has changed in the rest of the kernel code? I'm changed it to 100 and will see what happens, hopefully mouse will work.
Samsung Galaxy Note 3 SM-900T 32GB
Samsung Galaxy Note SGH-i717 16GB
HP TouchPad 32GB
Archos 43 Internet Tablet - 16GB + 32GB mSD
Dell Axim X50v - 128MB + 16GB CF