Just found this: https://bugzilla.kernel.org/show_bug.cgi?id=13544
the laptop (a thinkpad t500) has an integrated mobile modem. i think it is some kind of ericsson f3507g.
Seams like this is found by the cdc_ether driver. First I thought that some FOG users use the driver with USB network cards. But searching the forum (cdc_ether mentioned only once!) and reading other things like http://www.linux-usb.org/usbnet/ I really wonder if we need this in the kernel. @Tom-Elliott what do you think?