Okay, I've decided to flesh out a full rules set for creating full-scale economic warfare, so I'm starting this thread for people interested in contributing.
What I've got so far:
Corporations are treated a bit like a large-scale shadowrunning team. They are divided into divisions, which each have their own stats. For small B- and C-corps, these divisions are usually internal departments, like IT or Marketing, while larger corps (A and up) will have full-blown subsidiary corporations. Subsidiary corporations can have their own internal departments, which can make a large A corp both very formidable and also extremely unwieldy.
Each Division has Attributes, divided between Capital and Labor. Here's what I've got so far:
Capital Attributes:
Real Estate - How much space you own
Infrastructure - Equipment to improve efficiency
Production - Equipment for producing goods
Security - Physical security equipment
Enchantments - Magical equipment
Labor Attributes
Size - Number of people you got.
Savvy - How clever your people are. Affects their capacity for learning and ability to adapt to new situations.
Education - How knowledgeable your people are. Gives them more options when confronting a problem. This includes skills. Not all education is fancy book learnin'.
Morale - How loyal, idealistic, and industrious your people are. High morale not only increases how fast you get things done, it also makes it harder for enemies to infiltrate your ranks.
Magic - How much magical power you have.
Corps also have the Special Attributes Size, Reputation, and Corruption, none of which have I yet worked out how to handle, but they would be aspects of the entire corp rather than divisional. Corruption would probably be related to Morale.
Divisions also have Actions (which work like skills), Qualities, and Assets (Prominent people or unique technologies. Examples of Assets include Damien Knight's Space Mage and Ares' Bug Spirit Guard Animals).
Edit: For NPCs, C corps have stats in the 2-4 range. B corps are in the 5-7 range. A Corps have in the 8-12 range and are able to have C and B corp subsidiaries. AA Corps have 13-16 and can have up to A subsidiaries. AAA Corps can have up to AA subsidiaries and will have stats that are 17+. For PCs, it'll be another special stat, which I've added above.