HiJackZX1...let me let you know personally that if your USB hubs are powered via the PC, none of your USB accessories are going to work. I've just wasted $30 buying 2 HUBs thinking they will do the trick. So yes, there WILL be a power issue.
Heres what I'm doing, I have a case very similar to the ampie, made by mo-co-so.com. My mini itx mobo has 2 USB slots. Trunk mount..I have a 15' male to female USB extension which I planned on hooking the darn HUBs to. Since that did not work, I ordered 3 additional extension cords. During the process of researching ways to connect my USB accessories, I ran into this Vantec Enclosure http://www.newegg.com/Product/Produc...82E16817145138 since I needed more space 2.5" HDD could offer. So I order that w/ a new HDD and it happened to also be a USB 2.0 HUB w/ 3 ports.
Heres all the USB accessories I need to connect:
Sirf III USB GPS
Griffin Powermate (Controller Knob to use for audio and other functions)
External Pioneer Slot Loading DVDRW
BTC Mini Wireless Keyboard w/ mouse joystick
Lilliput Touschreen via USB
Vantec USB Enclosure.
After I hookup the Enclosure, I will have 4 USB ports available. With the 4 USB extensions I have, I will run the Powermate, Ext. dvdrw drive and Lilliput touchscreen. I'll have to deal with the Keyboard later.
I know I rambled on a little bit, but it sort of give you an idea on another outcome.