We have a Houston Instruments DMP-50 pen plotter recently donated, which is an old roll or sheet pen plotter than takes up to 36 inch wide paper. Serial port, I think.
I think we could find a vinyl cutter swivel knife holder that would fit this, or the plotter or the knife holder modded to fit. This could be great for printing out full size templates, blueprint style plans, and for cutting out sign vinyl to make our own sighs and banners. Aftermarket vinyl cutter blade holders are on eBay for very cheap prices now, under $20 will get a holder with a lot of extra blades.http://www.ebay.com/sch/i.html?_odkw=vinyl+cutter&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR1.TRC0.A0.H0.Xvinyl+cutter+blade+holder.TRS0&_nkw=vinyl+cutter+blade+holder&_sacat=0
Roland seems to be the most widely available, then second is Graphtec.
Then there is the issue of swivel offset compensation. Without swivel compensation, corners will be rounded and ends of cuts won't quite meet up. Please do not confuse this with cutter offset in CNC and G-code, which is a fixed outer or inner offset. With a swivel knife, the blade must drag slightly behind the centerline so that it will swivel to line up with the direction of travel. That means if you simply move the cutter in a square, the corners will be rounded off. So the centerline must go past the corner point by the offset of the tip, then smoothly move back into line with the direction of travel after the corner.
The old Graphtec I have (had, it doesn't work any more) uses a small triangle in a square to test offset cut compensation. Corners should be sharp and weed cleanly.
Some cutters have compensation in firmware, some in the driver, some rely on commercial sign cutting software to accomplish this. I think we can agree that free is good, open source and free is better. It looks like Inkscape has an extension called InkCut for offset cut compensation now, but it may only work with HPGL output for HP plotters.https://www.timewasters-place.com/inkscape-and-plotters-the-3rd/
Inkscape is free and open source for Windows, MacOS, and Linux:https://inkscape.org/en/
Drat, it only outputs HPGL and only works in Ubuntu Linux, and Houston Instruments is not on the list of supported plotters:http://inkcut.sourceforge.net/