Here's the test form I used - it's about 22" across and 2" thick.
Here's the Grasshopper definition.Inputs are the object(s), sheet thickness and size, and distance between parts. (The link to download is at the bottom of this post).
The definition takes the 3D form, breaks it up into layers of the specified thickness, and then nests them on the sheet(s). In the image below a 48" x 48" sheet at 0.7" thick was specified.
You can download the RhinoNest demo and use it for 30 days. The download includes the Grasshopper components.
This link is to the zip file with the Grasshopper definition and a Rhino sample file: Download Here