A backbone of rice krispy treats? Ingenious! Bet that one was fun to transport
Having built only one gingerbread house before the Empire State Building, I already realized how important considering the transportation of the house would be, especially when it's going to be carried around the room during the auction.
I actually spent extra time on the base for the Empire State Building. I used 2 sheets of 24" x 24" particle board sandwiched together with 1"x2" planks running inside. The planks were spaced so the two outer most planks could have 1/2" copper pipe slid all the way through. The copper pipe was cut about 3' long so 6" or so extended out each side and there was 2 copper pipes one for the left and one for the right... this provided 4 sturdy handles and a very solid base so moving the "monstrosity", as my wife likes to refer to it as, was very easy with 2 people.
We called a friend who had a mini-van to help transport it to the auction. I was lucky to find that there was a whole 1/2" of clearance between the top of the tower and the door jam (after the building was dismantled into 3 sections)!
My recommendation to anyone who is faced with the possible transportation of their gingerbread house, is to use a solid non-flexible base 3/8" think or more of particle board or even 1/2" to 3/4" foam-core if you do not have the tools to cut particle board. I buy my particle board at Home Depot and ask them to cut it for me before I purchase it.
I used 1/4" particle board this year on the UP House and ended up doing quite a bit of damage to the fence. If you are faced with moving a house with a base that wants to bend on you, get a piece of plywood to slip under it like a big spatula.
Here is an example of a Gingerbread Space Shuttle built on 1/2" foam core.