I would also suggest the slide show. You could do it as a DVD or as something like Power Point and be sure you have Disney music playing softly in the background.

You could make it be about all the things that have been built for them. If you have pictures of the "family" house being built, include it. A card made by your DD's shows up on screen then your DD's hand it to them in real life. Then may be a desert for the dinner you're about to have. Then a few pictures of the Dream being built and then the next screen would be the picture you created last night with the dates on it.

No matter what you choose, it will be fun I'm sure!