Just a question, would they be returned?
Most probably, my "help" with shipping would be to pay the return postage. It is not my intention that these would be gifts to myself or PDX or anything, nor do I wish to steal anyone's creations.
For example: I'm also a part of an organization called SciBrick http://www.scibrick.org/
which does science-fiction based lego displays, rather than medieval. Well, SciBrick did a fairly big show in Houston that was a part of a Memorial Gala for the Challenger. Various members of SciBrick mailed their creations to Houston so they could be displayed at the Gala.
If you look here, you can see a red shuttle in the background to the right: http://www.brickshelf.com/cgi-bin/gallery.cgi?i=557177
That is what I shipped to the event (and shipped back from the event, etc)
Since I leave for PDX on wednesday, I'd suggest making sure your MOC is shipped no later than February 4th.
I promise to treat your creation with the same care and love I treat my own, and it will get back to you in as good as condition as it got to me.