Thanks for your documentation. I needed to expand my partition for the same reason: I've dd'ed an old disk to a new disk.
Step 1 worked for me on an extended partition. The fdisk's "p" command shows start/end cylinders for the extended partition and the partitions in that. I've deleted the extended partition (all sub-partitions are deleted), created the extended partition ("n", "e") and re-created all sub-partitions with the start/end cylinder values from the "p" command above, except the last sub-partition I wanted to resize.
I've used the GRML boot disk. For this, you have to "/etc/init.d/lvm2 start" after step 2. This is because LVM isn't active after default boot for safety [1].
Again, thank you very much! This tutorial is awesome!
[1] http://grml.org/faq/#lvm