Thanks to all of you for the advice and links!
I also just downloaded and tried the nightly Linux build of the all-new MakeHuman program, and while still in alpha phase they already have many new models with different ethnic settings, and they just implemented export into OBJ - I'm glad they finally developed it this far because the several-years-old version I used previously for this head (in the pics in this thread) produced very clunky, hard-to-work-with models that couldn't be varied too much.
The newer MakeHuman model heads are much easier to shape, change, and they don't have tons of extra and unnecessary polys like the old one that I had to work out by hand.
The links are still very good though, as they'll give me ideas for various new heads.
As a side note, I can also use the modeling technique I used to put photographs of *real* people onto low-poly heads - I actually thought about doing this, effectively putting real people (whomever would volunteer) inside the game, then adding variations of hair color etc. (by first doctoring the photos), but I didn't know if enough people would volunteer.
If this idea interests any of you - putting real faces from developers and contributors inside the game - you're more than welcome to start a list of volunteers and if enough people sign up I'll go that route. Also, I can alter the facial shape of models from real photos as well, so there's no need to worry if you think your face might not look too good as it is for a soldier. (Heck, myself I've gained a bit of weight and now consider myself to be "ability-to-fit-into-a-chair-with-arms-on-it-without-the-employment-of-a-shoehorn-impaired", but altering such characteristics shouldn't be too hard.) Also, I'd be willing to alter the shape anyhow if you don't want to be recognized, for privacy purposes (If such a thing is done I can accept private emails of photos).
Please do not simply start taking pictures and sending them though, as they need to be done in certain ways and at specific angles.
Otherwise, I'm just going to use the new MakeHuman models and work from those.