Sure there is. It's described right in the DM Guide under the section "Skill Challenges."
This is 4e, anything you want to do that's major, and isn't combat, can be accomplished through manipulation of the skill challenge system.
- Levels matter. DCs are set based on level, skills are improved based on level.
- Morale matters. This can be managed through the skill challenge system via supporting roles. This is a good use for Charisma based skills.
- Everything is abstracted here, so there isn't anything to be run. You reduce your battles to a series of History, Religion, Arcana, Endurance etc rolls.
- PC's have gobs more leadership ability than your average Joe NPCs. And in fact you can do degrees of difference based on how many failures your PCs rack up through the challenge.
I understand that this is probably not what you're looking for. But this is the 4e's design. If it's not skirmish combat, then it's a skill challenge.