It will be used by a Navy SEAL team. Ofcorse the thing is, keep the price down.

One friend told me to just use 440-C, with a Rc of 54-55. I'd like some more ideas.

Machete will be 18" OAL, 13 1/3" blade. Bead-Blasted finish.
2" wide, maybe 5/32 thick.

What would you use?

S30V would be a very good choice, especially if you are going to bead blast it - making it more rust prone. S30V is more corrosion resistant than even 440C. The hardness you mention is fine, but S30V can go to Rc58 without compromising toughness, so why not make it hold an edge longer. I've made machetes from 154CM, using a very convex edge, and it's a very good tool. That's my take anyway.

one thing about 440c.....rockwell must be above 56c for best rust resistance. I have some of that other stuff jerry is talking about..........will try it soon!