Sorry, no such thing.
There is also no such thing as "enough vises".
I've got a big old Record No 7 machinist vise that weighs over 100lbs, a 6" post vise that's well north of 100lbs, and a 4"er that's not that heavy or good. Oh and an old wilton bench swivel that's got 3.5 or 4" jaws. That sounds like a lot, but I'd really love another bigger post vise to keep next to the anvil, for beating on, and put the other outside for angle grinding billets.
I've got the big Record mounted on my welding table, but id love another on the bench for heavy filing, in good light. Swivel vises are a nice convenience for small stuff, but the smaller ones in my experience won't stay still long enough for heavy filing, grinding, or cutting.
Personally I would make finding a 5" heavy post vise your top priority. Buy or build a heavy stand that you can bolt down, and you'll never find yourself cursing it's inadequacies. You'll probably end up wanting more of them, but the post vise is the most versatile and useful to knifemakers imho, even if you're just doing stock removal. Shop local, flea markets often yield old vises and usually much cheaper than ebay. You should be able to find a big post vise for around $100 with luck.