I'd gladly make a modified version of my needle cutter designed to mount to the Rascal. I was just waiting to see some builds first to get a feel for how the tool mounting is accomplished. I've looked at the DXF files, but there doesn't seem to be a lot of info about which piece is which...I can figure most of them out but I can't picture the fully assembled Z in my head yet.
I saw Doug Miller's post on the FB group with his Z coming together - but no tool mounted yet so I'm still not 100% sure how the mounting is achieved.
I can think of a few ways it could be done.
Cutter designed to mount in place of the spindle with the same bolt pattern.
Cutter designed to mount in the spindle mount - loosen the screws, remove the spindle, mount the needle in it's place.
Cutter designed to ride tandem with the spindle (Could run into some clearance issues though.)
Modify the plate the tools mount to to create a quick release setup allowing changing toolheads with minimal or no tools.
Modify the plate to use a needle fulltime instead of a spindle for a slightly cheaper build.
But...as David who introduced us to the needle cutter
commented yesterday the needle cutter isn't limited to any one machine or design. It's just a concept that can and has been applied many different ways.
With a Rascal up and running with default spindle you could cut wooden or plastic parts to build a needle cutter out of. Or you could strap a cheap $20 extruder to it and use it as a makeshift 3D printer to print one. Heck, you could even strap a cheap laser on and cut one from thin ply. Tons of options!
I'm more than willing to adjust my cutter design(s) or create a new one for the Rascal - just need some more specifics on your builds and goals to make it happen