My dream bike trailer:
sub 12lbs
hard case (31" in size),with detachable wheels (16"), has retractable wheel hubs and bike connector assembly.
Unfolds to become a hard case bike trailer (enough room to carry a huge backpack or at least 1 child), with loading capacity of over 100lbs...
bonus if you can add suspension without much weight penatly!
Oh but we can only dream...