It's working like a charm. You need to compile in support for USB, and usb-mass-storage. Then you can mount your cards from sda1, sdb1, sdc1, sdd1. If theres other scsi-disks or mass-storage units on the system, the devices may be different. The first will be the Compact-flash/Microdrive port, the second is the SD/MMC, and the order of the last two I don't know, since I don't have such cards.

It also works at USB-2.0 speeds as long as you use the EHCI usb-subsystem.