If this is a knife for wilderness SAR missions, I'm thinking it should be able to do the following things well:
1. Cut branches up to ~2" diameter for shelter/fire/litter construction. (yeah, any SAR team will likely have actual litters, but it doesn't help to have the capacity to improvise, and shelter/fire is still a good idea if you have to hunker down).
1a. Should be able to split wood reasonably well, for fire-making in wet conditions.
2. Function as an impromptu pry-bar - best reason to carry a big knife, rather than a folder/saw/prybar combo.
3. Ability to cut line and webbing - i.e. small serrated region. As much as I dislike combo blades, this would seem critical.
4. Might see occasional use as a digger/shovel. Not super likely, but it could happen, and a knife is a likely piece of gear to press into service if you're not carrying a shovel.
5. Should be light weight and easy to carry.
I'm thinking an NO-E or Satin-Jack Tac fits the bill nicely. If the mission were in a less wooded area, something smaller would be good, probably a Mean Street or Badger. A "Rescue Street" would be intriguing - general Mean Street dimensions with a rounded tip and serrations, similar to the "Rescue Stryker" by Benchmade.
IMO, most Busses make excellent field blades, so there's not a whole lot of need for a speciallized SAR blade. People can pick one from the lineup that fits their needs.