Another point about the creation of an army to note would be that if it's a large group.. well.. sovereign nations have this peculiar facet where they take the movements of heavily armed soldiers into their territory quite seriously. Adventuring parties tend not to raise quite the same flags because they're smaller, and because they tend to spend a lot of money in town. An actual army, particularly one that billed itself as such, would likely face a number of barriers that an adventuring group would not necessarily.
As well, creating an 'army' begs the question of political purpose. If you're selling services to the highest bidder, you have, in effect, a mercenary army. If you're sworn to a nation or cause, you will necessarily find yourself at odds with those that oppose that nation or cause. While I realize this seems straightforward, I just figured I should mention that the formation of an army would have some likely serious IC implications.
