At least we know that the idea of a 12" Dog Father is popular.

When I've used my Spyderco/Hossom Forester to clear trails (usually branches above head level), all I can really think about is how much nicer it would be if the knife were HEAVIER.
The Forester is a 9" blade that weighs the same as the SOD (or Becker 9), so it's not really a heavyweight, but when I use it for chopping I tend to wear myself out just pushing on the knife as I swing. Ideally you just swing the knife, and let the weight of the blade carry it through the branch (virtually no wear on your wrist that way). If the total weight of the knife is just over a pound, it doesn't get very far, and you end up making a lot of swings, also wearing you out. I also have my 24" Machete, but it still isn't very heavy and can't really chop (it does work well on the light stuff though).
I guess I have more strength than endurance, so I would prefer a knife will get as much work done per swing as possible. IMO that means long and heavy.

But what if 12" and 3/8" thick is TOO heavy, and I come back wanting a 1/4" version? Could be. I certainly wouldn't complain about a normal Dogfather stretched an extra two inches.