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.
Having a closer look I think you can get rid of the nuts for ABS.
Screws easily cut their own thread through ABS and are then super-tight.
Without nuts this gets smaller.
Sinkhole-screws may also be used to make it even smaller.
What thickness of the ABS-rings and what solidness did you use to hold what kind of weight?
How did it work out?