Are larger unit sizes only buildable in, say, large cities or places with the relevent barracks? Or are they simply prohibited by cost/research?

Here's kind of how it works:

Researching:

In Elemental, Logistics matters even if it's abstracted.  You don't research a type of unit.  You care about things like logistics, training, equipment.

This is how you get access to different sizes of units:

Then you design your base unit (this is how I got "Fabio"):

As you can see here, at the start, he's pretty weak (but stylish). 

His equipment is a stick so there are no points in equipment.  There are, however, 4 base points for training.

It typically takes a town 1 turn to produce a given point (at the time I'm designing it, the game will provide an estimate based on the state of your towns).

Then you make your unit.  These guys come right out of your town.

So you can't just have a village of 100 or whatever people and build a legion of soldiers there. These people are coming out of your population.

And half your population are female so you can't use up all of them you can only use half of them UNLESS your faction has purchased the egalitarian option at the start of the game (then you can end up with females in your army).

You can combine units into an army that will fight together as one. In the cloth map beta, it's not terribly impressive.

In the actual game engine, it's considerably better even in pre-beta:

This is a single army which is made up of my sovereign, a princess, and a party of Fabios. Eventually, the Fabios will all look slightly different from one another (other than outfits).

So when you have armies running around the map, you'll be able to see, at a glance, what they've got. You can still click on them and get all kinds of details but you can also obviously tell if one group is a bunch of peasants (these clothes are a bit too fancy right now) with pitchforks and the other group are guys with armor and such that it's not going to end well.

Sexism FTL?

Will be interesting to see the mechanics that go into it.  I'm hoping for a breeding rate trade off.

Precisely. Lower birthrate but you can use all your population.

If unit design can be gender based, that is both awesome, and horrible at the same time.  Along with the witch reavers and blade dancers, we'll have man eating strippers or something.

So female soldiers planned for Gold then? I thought it was CariElf (sorry if I'm mistaken) who didn't see it possible for then. I know it supposes extra work doing more models and the associated stuff.

I don't know who witch reavers are, and blade dancers sound like Lineage II. I'd bet that Stardock won't use cows so it's up to the player do add all the "aberrations" that they are fond of (I enjoyed playing a female Blade Dancer in Lineage II but if I had known of the stupid revealing armours, I'd have thought about it twice ).

Oh! And good to know that we can combine different types of units!

"Unit design really demonstrates a key part of the economic system"

Wait a minute ... tick tock tick tock tick tock ..... *several hours later* tick tock ahhhhhhh

If it is the same with the rest of the economic, could you like stuff 200 more ppl into the farm to get more wheat or pumping some workers into the smith to get the army faster?(or to get more babys ... ya know)

Can I get one of those?

Hmm, there's more cool new information in this thread than in the Dev Journals.

This would seem to offer up all sorts of routes a player could take in designing their military.

What is the targeted duration for building a legion of 1000 armored fabio when training 1 requires between 11 and 14 turns?

I'm really hoping they push the envelope with how many units can be shown on screen at once.

On a side note I was thinking about the time tables it would take to build massive amounts of troops as well. I hope they tweak those time tables shown. Maybe we'll be able to iron that out when we're concentrating on balancing things. It will be hard to have truly epic wars if it takes you a week of real life time playing one game before you can build a 1000 men. It will also depend on how long each "Turn" is in game. If each turn represents 6 months then those time tables seriously need adjusted. If each turn represents 1 week or 1 day then 17 turns to train 1 unit isn't too bad.

We'll probably need to wait until we have more info and it comes time to talk about specific balance issues. Not to worry though as that's a pretty important part of Beta Testing and I'm sure we'll spend a few months with a later build doing just that.