As far as I know, there is no such thing as of yet. I am no addon maker, but as new weapons are added to OFP on a regular basis, why not make this an option? Using a script, add a "Carry Body" option to the players action menu whenever he is near a dead body of his side.
As soon as he uses it, the body would have to be displaced (0,0,0) and a weapon, carried on back (much like LAW and AT-Launchers) would be added to the players menu. He would have to drop his LAW etc. however. If he then decides to "drop body", the victiim would be moved to the location and the weapon would be deleted from his inventory.
I am afraid, there would not be any carrying the wounded, though, at least I cannot think of a way to implement this.
As a mission-maker or scripter, however, you could monitor your soldiers and have a "heroic rescue attempt" as soon as someone was unable to stand up anymore, meaing a couple of helos coming in low and fast and fending off the attackers long enough for the wounded to crawl to the medevac.
But I am afraid, that would get pretty much "worn out".
And I can feel what you feel. We also undertake every effort, and might it cost our lives, to rescue a wounded or dead firefighter.
It is all about respect, trust and friendship. Whoever does not understand this should stay out of military, police, ems or firefighter business.
Cheers
PiLLe