I did the copy this weekend using the SLAX LiveCD distro. Everything went flawlessly but it still took on the order of 9 - 10 hours to copy 215GB from the old disk onto the new 300GB drive. I did the copy through KDE using "cut/paste" and then did another copy (for a different disk) using "cp -r -p" which also looked like it was running at about the same rate (approx 6MB/sec).
I'm assuming that is just the way it goes. Would a NasLite feature allow the unaffected disks to still be available during the operation?
I hated having to shut down the box, since I had an uninterrupted run of 170+ days of uptime, but such is life.
Thanks.