[Imp]

Depends very much on the country & indeed individual commanders.
If talking WWII how many Russian Italian Commanders do you think directed from the front to name but 2, even the Germans the good ones but by no means all. One would stay behind in the command post the other forward often with the top guys rotating the roles each day so had first hand experience of the tactical situation so yes you could call your HQ a 2 man unit but he is supposed to represent the chain of command.

Even on the biggest map if your HQ & associated gear is on the map you have seriosly screwed up thats why they had transport to get back to it.

You could indeed depict a raid or break through to your HQ if made some units. Most people would be none combatants so low experience pistols maybe some SMGs or the odd rifle, grenades doubtful though could chuck a wrench. These would be clerks cooks maintenance & the like thrust on the front line.
Unless a combat formation managed to fall back their fate is pretty much assured thats why they are not on the map.
Totaly vital guys without whom the grunts can't survive let alone do the job.