You are correct about the power. here is an article I found about apple branded speakers, and they are made by harmon/kardon, not klipsch (similar companies though). The problem is apple computers have 10 watt usb ports, but normal usb ports are only 2.5 watts. Oh well.
the article can be found here:
Mobile-2.2Ghtz Core 2 Macbook, 4GB ram, 160GB HDD
Server-Dual 1.42 MDD G4, 1GB ram, 4 random hard drives.
PC-C2D 2.4Ghtz, Asus Commando, 2Gb ram, 3 hdd's in raid 5, 8800GTS.