Technically, I don’t know if we’re supposed to post others’ work, but I found this and thought some might like to see it…some of you may have already, and know this person, who seems French by the title of the video, but this is the longest video i’ve seen so far of a working pack!! 
Enjoy!
That would be these fellers:
http://www.gbprops.com/forums/viewtopic.php?t=59
And they did dang good work on them there packs.
~5B