I just tried a Deal Extreme SKU10113 USB 2.0 to SATA/IDE 5 Component Cable and it worked without any issues. N810 with Diablo firmware, nothing special except USBControl installed.

Here's an image of a 160 GB hard disk connected to the N810. The disk is a flaky one, previously installed on a Linux desktop machine, containing several ext2/ext3 partitions. USB-A adapter is self-made from the cable that came with the N810. (Sorry about the unreadable text in the image...)