The recent discussion (Sleeves' post) got me thinking - what about a mod where you get metal via little supply vehicles that spawn and drive deliveries to and from your mexes.
Supply routes:-You get a starting nexus/hub like in Arena mode
-Mexes don't directly produce metal
-Nexus produce energy supply vehicles (ESV)
-ESVs travel to a mex, disappear and boost the mex's energy supply bar
-Mexes produce metal supply vehicles (MSV)
-MSVs travel to the Nexus, disappear, you get metal
Supply tactics:-Supply vehicles have very low HP and no weapons (raid opponent vehicles and protect your own)
-Mexes have improved HP but take serious damage if they run out of energy supply (raids focus on supply vehicles)
-(Optionally) buy upgrades for improved supply vehicle speed, HP, shields, weight
Economy curve:-Mexes produce MSVs based on energy supply bar (more ESVs=more MSVs, diminishing returns)
-ESVs cost energy, number produced is percentage of overall energy income
Choose vehicle types to match terrain and your tactics:-Supply vehicles come in several types (hover, spider, amph, air), which you select at the point of production
-Supply types have pros and cons (supply amount, speed, HP, flight etc.)
To make supply vehicles low-APM:-Mexes can be given rally point order like a factory, which MSV inherit
-By default, this is a move order to Nexus
-ESV get a default move order to a random mex
I think this could result in a very visual, raidable, tactically interesting economy. I'm not sure whether supply vehicles should be controllable, and how often they'd be produced by default. What do you think?