Fantastic utility. I recently had to re-shape (twice), re-size and even re-layout an existing and poorly thought out 5 1TB Disk RAID4 array. As I couldn't use my running kernel or installed mdadm (too low a version for both) I boot to System Rescue CD 1.5.4, which had the requisite kernel version and upper mdadm version, http://www.sysresccd.org/ and was able to do everything. It took 48 hours for each operation (3 separate operations), but in the end I had a left symmetric, 6 disk RAID6 array. The production OS was able to assemble the device and mount the volume without incident!!
Thank you for your hard work and attention to detail.