In the next few days I'll begin populating a 14.04 repository on the apt machine.
We were running short of disk space, so I added another old drive and added it to the LVM setup. Most of the 'how-to' is identical to my post on extending a logical volume, but I've rewritten the post to reflect the additional steps required to add a new disk.

The post is here: http://hcmc.uvic.ca/blogs/index.php?blog=11&p=10175