Best place to mount a vise?

Anybody have luck with a mobile vise base (something you can use without the vise moving/wobbling/migrating)?

If so, what's it look like, how's it made, how much does it weigh?
Mine is a 1 foot tall chunk of 20ish inch culvert with a forged ford I beam cast into it, offset, with concrete. I welded a piece of 12 inch long C channel to that and welded corresponding nuts to fit the vise. I can stand on the concrete base to offset any movement when torquing on it. The offset gives me leverage to roll it around. I know... Pics. It weighs a lot.

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