12 ounces? That's way too heavy; you'll never use it. Just for kicks go get a 1/2 lb weight and tie it to your ankle and walk around for 2-3 hours. Oh yeah, try walking so no one notices that you're walking funny. Not much sense in advertising.
A boot knife needs to be thin and light. It's a back up weapon, not a go cut firewood tool.
Tommy Lee makes one of the classic designs, He's a bit old now, but they've put it into production,and you can find them all over in your price range. Here's one he did a few years back, signed engraving by Symon Lyton.
For a few bucks more you can get a really nice knife custom made to yu specs. Here's one Steve Fecas did for me last year. Mammoth bark scales pushed the cost over $300, but you can do micarta for a lot less.
Or, if you're willing to wait, look around. I picked this Norfleet New York Special up for less than $200.
Another thing you need to watch is the sheath; you want leather. Kydex will rub a hole in your socks, your boot, and your ankle. But the sheath needs to be thin andfairly stiff, too bulky and you're right back to something you'll quit using.
