Still playing devil's advocate :)

>So, I guess I'm wondering if we are supposed to mimic  hunter/gatherers, why do  some here only promote >meat/fat?

Me too. I recall my first introduction to paleo was the suggestion that paleos had *hundreds, perhaps thousands* of food sources to choose from. 

>Why do we surmise about the diets of dead hunter/gatherers when there are living tribes we can learn from?   

Apparently the all-meat advocates believed the only paleos of import were those stuck in the northern regions of Europe during the last ice age.

>They stuffed themselves with pemmican all winter.

Who "they"? Those paleos who hadn't yet discovered or had no interest in fire?

>As all the ingredients of pemmican are edible to Primates in Nature it certainly is Paleo by my (oldest and still >the best) definition.

Ah, but where'd the sharp stick come in with regards to rendering fat?

>We are are all nuts:

I've long known I am.

>And I've really been wanting to drink a lot of water every day -- no
>force feeding, just satisfying that desire.

Not related to pemmican - just an observation. I've noticed in the past that my "craving" for water is directly proportional to the amount of meat I eat. THe more meat I eat, the more water I drink.

>Is there a way to calculate the minimum amount of fat needed, say, per kg of
>weight per day?

Seems like you are asking the question the wrong way. Since we know there is an absolute protein limit, and those who are carb-sensitive have some sort of carb limit (though not as writ in stone), then whatever is left over should be... fat. 

So, if you eat 2000 cal per day, and you limit yourself to 100g protein and 50g carbs ,you're looking at

2000 - 400 - 200 = 1400 cal fat. And 1400/9 =  156g fat. Or something along those lines.

Now, my brother-in-law, who is also diabetic, tells me fiber plays an important role in offsetting carb intake. Apparently it's pretty much a 1 to 1 ratio (+1 for carb, -1 for fiber). He's not paleo, but I can't really argue with his results. He does a very good job of keeping his blood sugar in check and has reduced his meds quite a bit using this system.