Manually created campaign
 

OK, this is an idea I had which goes like this: I'll play a series of battles (up to 7 in total) versus the AI. The forces will be selected by me (both mine and the AIs). The outcome of the battle will have a clear impact on the campaigns evolution, but so will the casualties that the two sides suffer. In other words, sometimes it will be better to forfeit a battle than lose a large chunk of your force. Before every battle there will be random events that will be in your favor, or against it (extra reinforcements, better support, sudden retreats of your units, morale drop etc). These will be determined by two dice. The dice will also determine when will I receive reinforcements (these will be on map units that I will not move forward until the specified time.
Units that do not withdraw from the battle area, will not replenish losses. For instance, lets say that an infantry battalion lost 25% of its force in a battle. If it begins the next engagement immediately without withdrawing, then I'll purchase as before, but 25% of its force will immediately exit map(which obviously puts it in a greater disadvantage).
Since its a bit late, I wont post the campaign details yet. In a nutshell, it'll be a Greek mechanized infantry brigade defending against 2 Turkish mechanized brigades and 1 armored brigade+1 more armored brigade coming as a follow-up force. Both forces can get extra goodies from their respective Corps commands.

Re: Manually created campaign
 

I'm doing something similar with my 13th MEU campaign.

First you need to buy ALL the core units needed for the player side, each and every one to be used at any point in the entire campaign. Auxillery units that are only in a single scenario aren't a problem.

Each scenario you can set any core units not used for that particular scenario to reinforce turn 50, just insure your scenario is 49 turns or less long. That way a tank destroyed in scenario #1 but not used in scenario #2 is still destroyed in scenario #3 where it may have been used.

As to the AI ... just buy those as needed scenario by scenario, remember they are lemmings, so most won't survive from scenario to scenario.