MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
You can use bowden extruder. Any E3D V5 can be mounted on the X carriage without extruder. Files are uploaded here. But for NEMA17 bowden extruder that can be attached to M8 threaded rod you will have to look somewhere else.
If you want NEMA 17 extruder that sits on X carriage than no, there is none I am awere of.