[RedWurm]

A Magical Technocracy:

a nation run by a small elite of magical leaders, without much support from the people or the religious establishment of the nation they control. they have very poor PD, possibly some kind of dominion penalty and have trouble reducing unrest.

their armies are magically animated golems created by the national commanders. other than the basic chaff units, they have a hefty gem cost and, if possible, increase unrest in the province where they are created in line with their gem cost.

as the main restriction on golem spamming will be gems, the commanders need not be particularly powerful mages, while the properly powerful dudes could be very expensive indeed and old age will be rife.

Also, I like Aezeal's idea of summonable fortresses. this nation might possibly have a normal fort that could summon the basic chaff spammers, just to keep the locals unhappy, whereas the better commanders could only be recruited from summoned fortresses - which would necessarily compete with your army for gems.