I'm sure I read somewhere that the code which tells the POW truck to pick up stunned infantry, and the code which tells a building it is a prison, has been cut.
I had an idea for doing it - when an infantry unit is killed by a SURRENDER weapon, the unit disappears instantly and a crate which has that units surrender animation as its art is created. Picking up the crate gives you money, or if it is picked up by your side, you get the unit back

Not sure how you would code the side dependant bonus though.....