These ideas quickly come to mind....
moving day (packing, boxes, trucks)
Unpacking at the new house
Paint chips for any new colors their are using in their new house
Fabric samples/carpet scraps, etc for anything new that they are putting in the new house
A blue print of the new house (or maybe just a generic blueprint to use as background)
If the new house is actually an "old" house, maybe you could see if you could find old pictures of the house (maybe from the town's historic society) and any info on the history of the house.... or maybe the current/departing occupants could help with that.
A copy of the newspaper article that is in the legal notices about the sale of the house......
That is all I can think of for now.....................P