Hint: The entry level is at USD475. ;-)
What that means is you cannot scan a signature and reproduce it, because the machine won't know where to start and where to lift the pen. We used something like documented here: https://wiki.evilmadscientist.com/Capturing_Handwriting#Capt...
This produces SVGs which have those individual strokes that the machine can reproduce.
I wonder if you could recreate signatures by examining the depth of the ink where the person lifts their pen, since that typically has the largest deposit of ink at that point, particularly with a fountain pen.
These are based on the EBB board which uses a custom command set rather than the more common GCode command set which is the basis for most CNC machines.
If you're interested in CNC I'd recommend going with something that is based on GCode as it's much more transferable. GCode is used in everything from $100 PCB engravers up to multi-million dollar HAAS milling machines.
The $150 laser engravers from Eleksmaker for example have an unused servo pinout on their control boards specifically for adding an accessory like an actuator for a pen. It would be trivially simple to swap out the laser module, which is held in by thumb screws, and replace it with a pen.