Where a belt holster becomes less than desirable is when wearing something like a pack where the waist strap covers up your gun.
Agree. You don't want anything under the pack belt or it'll create hot-spots that you'll not soon forget. A leather gun belt can also seriously pinch when some skin gets between it and the backpack belt (a properly fitted pack rides higher than a pants belt) and that hurts like heck. Most hiking pants don't even have belt loops for that very reason. For hiking and backpacking I use a Bianchi M12 military holster on my pack belt. The QD buckles on packs won't allow you to thread a traditional holster onto the belt, but the M12 can be attached over the belt- Bianchi calls it quick-lock or something.
If it goes into the pack it's not easy to gain access
Agree. I have an anecdote about that subject but it's too long for this post. In the pack = bad.
...so some form of chest mount is necessary...
Disagree; there are other options, like the M12 (for hiking, not running).
or a thigh rig which would probably qualify under your commando sentiment.
Agree, but not only for the commando reason. A thigh rig requires a belt under the pack belt- creates hot-spots as mentioned above, and the rig will create drag on your leg especially when you're going up steep terrain.
EDIT to add: My other objection to the hill people chest rig is that during the draw, at the most critical moment (when your hand is acquiring the gun) the gun is lined up with your off-side arm (the one that's unzipping the bag). They used to have a warning about that on their website, and suggesting your keep that arm in a pronounced elbow-high contortion to keep it clear. I don't feel confident I would remember to do that during a physical attack (man or beast).
Something like this chest rig from Clark Fork might be a compromise.
Agree in part. It
might be a compromise, but I had a chest rig for my Ruger Alaskan and the thing would thump my chest with every step- not painful but more like the Chinese water torture. I don't want to think about running in that rig.
BTW, I can't get to the link as the DoD seems to think that's adult material.
Everything with carry is a compromise be that look, accessibility, or comfort.
Agree. I'm just offering other outside the box ideas. The little .38 on my belt in a regular leather holster is completely accessible and comfortable, so I recommend that.