@Daedalus
Modellers = Blender (already an Amiga port existing), OpenSCAD ( requires several libraries)
Slicers = Slic3r (perl scripting, so newest mainline perl's Amiga builds), SFACT ( depending on python2.7, 68K-2.3 and PPC-2.5 builds are not new enough)
Device Controllers = Cura and Pronterface, written in C and Python...along with other options
These are all reprap project referenced software titles.
So...
Use Broadblues Blender builds to create STL's...
Then his perl builds to run slic3r creating G-Code,
Leaving only the problem of feeding this through Term or an equivalent to a serial connected or usb-serial linked CNC controller (RAMPS/Sanguinololu/SmoothieWare)
Optionally using SmoothieBoard controllers by IPv4 network
And just OWB browser upload the G-Code tomicroSD card and tell it to print that way.
The main requirement is feeding "Slic3r" or an equivalent slicing tool with an AMF or STL file and then feeding the produced G-Code to a SmoothieBoard(USB/Ethernet) or RAMPS open-hardware controller (SmoothieBoard is highly recommendable as I personally have made use of one of these on a sam440 and it appears with both mass-storage AND serial USB functions, the Ethernet option makes ALL existing network capable Amiga's with OWB able to use it pretty quickly)
Poseidon's existing usb-serial support along with REXX scripting for existing terminal programs gives a very simple but effective option for the serial option as well.
RAMPS controllers can take serial cabling directly and skip USB entirely as well (USB is conversion of serial to USB separate from the ATmega MCU used to control the machine from the ramps)
Sanguinololu schematics show where you can wire USB and serial as parallel options, but only one can work at a time.
Hopefully this is of some help,
www.reprap.org. www.smoothieware.(com?/net?/org?) have more specific information.
The FPGA on sam4x0 and the Xena on X1K A1 machines are not of any use unless you want to use Xena for an updated "LightWave ScreamerNet" or the FPGA's for some kind of hardware acceleration?
Edits are some autocorrect ion fixups...and adding a workflow description of what can already work.
Happy Hacking.