Several years ago Chip experimented with postcard models - regular sized models shrunk to about half size and printed on cards 8-1/2 x 6-1/4, with instructions and history and a place for address and stamp crammed on the back. d**n clever idea - I still think it's a flash of genius - but for some reason they never "took off" (excuse the pun) as postcards people would send through the mail. One obvious difficulty with them, besides getting marked and frayed enroute through all the paper mangling machinery of the mails, was that the minute you started to cut out the pieces, so went the instructions into unreadable bits!
Anyway, I got boxes of the old postcard models when I bought PMI and I think there might be some life in the things, if promoted properly. One model I have stacks of postcards of is the Panavia Tornado, which has the unique feature of having real swing wings. So I built one, to see if the wings work at postcard scale (they do)! Wingspan wings extended is a diminutive 5-1/2"; the span shrinks to 3-3/8" with the wings tucked back for supersonic flight.
These are photos I made up for the PMI website and catalogue, but the model itself is unretouched. Not bad for extra thick cardboard and dime sized pieces!