[dogscoff]

I'd suggest extended that idea so we "buy" supplies with resources;

Good idea. How about a facility a bit like the resource converter. Resources go in one end, supplies come out the other.
You'd need either a mix of resources to get supplies (ie 1000m+1000o+1000r=1000supplies) or even better, have it so that you can buy with any of the 3, but you get better rates on rads and orgs than you do on the others. Make those rads and orgs work for you...