Ok, this is going to sound weird, but I'd like to trade for their respective 2-disc editions. I know there are people out there, who actually detest the twofer editions.
I got them from two limited edition 2 Film Boxset DVDs, which I assumed were all 2-disc collector's editions. Cheeky Disney/Pixar bundled my two boxsets as:
*Cars/The Incredibles (single/2-disc)
*Finding Nemo/Monsters, Inc. (2-disc/single)