[heisenzombie]

There are plenty of companies that will custom-manufacture gaskets for prototyping/custom 1-off jobs, though I don't know if they're generally geared up to sell to end-customers in a streamlined way.

The tools generally used are "flash cutters"[1] (the industrial version of your wife's vinyl cutter); waterjet cutters; or laser cutters. They're all CNC controlled. You need a DXF or other vector file to send to these machines. They're often quite user-friendly now, with either projectors or cameras to help position the cuts on the workpiece, and vacuum-beds which make holding down material quick and easy.

[1] https://cutting-systems.co.uk/flashcut-flex-series-2/