I liked the design by BraunsCNC but needed to tweak almost every aspect of the models, so I remade all the shapes in OpenSCAD to make it really easy to modify all the parameters. You'll need a basic understanding of how OpenSCAD works to use this model.
See the original design for a video on what the tools are for and how to use them.
Usage:
Open vise.scad in OpenSCAD. Parameters that impact all of the tools are at the top of the file. Scroll to the bottom of the file to see examples on how to customize each individual tool.
Modify the magnet() function to swap between round or rectangular magnets.
The attached sample file is for a 4 inch vise with 8mmx2mm round magnets.
The author remixed this model.