Great effort, Beaver. With those smaller units you inspire the captains to divide their regiments into smaller groups (cav-arty platoons etc). Just to use it when playing free, of course. And that would effect even the players who isn't a member of a regiment. We really need to add more tactical play to the game, you see.
I know, of course that's not what you're going for, I just wanted to throw an idea was all. Anyways, I think you should limit the reggies to 27 people, consequently you can squeeze 2 divisions (4 reggies) to the army (total: 108 people). There are a lotta regiments around here, think it'd be best if we embrace more regiments. Plus it'd be more fun and would be easier to split up the army for the Generals.
As for the greater units than division, screw 'em. 
Long story short:
Platoon = 4 players (I suggest to use it when not playing event)
Regiment = 27 players max.
Division = 2 regiments (54 players max.)
Field Army= 2 divisions (108 players max.)
Voilà! Simple and more importantly, simple.
I disagree wholeheartedly.
First of all, what we have are companies, not regiments. All of the MM community combined hardly forms even a few scaled down regiments or arimies. Let's look at the numbers:
20 = 10% of an actual company, which was about 200 men (for the sake of arguing)
A company was usually split into two platoons, of about half a company (10 men each, by our scale)
A battalion was comprised of several companies - at least two, and sometimes upwards of 4. This would mean 40-80 men.
A regiment consisted of at least two battalions, usually more. On the low end, this would be 80-160 men.
An army consisted of many regiments. So even with just two regiments, that would be 160-380 men (<- sounds about right, considering our events.)
Now, consider this: the best turnout you can probably expect at any event is 50-75%. That means you need to recruit a good deal over the amount of men that you wish to field at any given time. Therefore, we would need to recruit, on the absolute low end, 30 men for a given company. 60-100 men for a battalion. 200+ men for a true Regiment.
Right now, the largest division we have are battalions. These are basically multi-company units. Limiting them to 27 men is ludicrous.