I'm sporting a usbless Karmic as well. Its takin my webcam out too!!! ref thread: http://ubuntuforums.org/showthread.php?t=1384743
The bug number is: #445160
The URL to report the bug is: https://bugs.launchpad.net/ubuntu/+s...ux/+bug/445160
Please report your bugs so the community knows its out there and can fix it.
P.S. It seems to me the nature of this problem is somewhat intermittent, and can be fixed by a program that regularly scans the usb system. Suggestions?