I missed this post apparently.
That's pretty cool that you're undertaking such a project.
Applications that come to mind at my specific company:
Conversion of STAAD model output to 3D Geometry. This could be done for either angle-iron communications towers, centerline modeled pipe structures such as offshore platforms, structural skids, and steel buildings. Typically our engineers model to centerline of pipe, or top-of-steel, CL flange, for standard extruded steel (W, C, L, T, etc)
STAAD can output to .dxf with either a crappy basic 3D model that's not terribly effective for design documents, or can export the centerlines used for analysis. I've used some basic LSP routines to take the STAAD output linework to create cylinders for structural pipe and have the Autocad model completed in a matter of seconds, rather than having to remodel the entire STAAD model. I remember that actually being one of my first "lesson projects" to undertake LISP writing and I can't remember if I was personally successful or if I ended up cobbling together someone else's routine I found on the net
I could see it being beneficial for sure, but the problem I ran into before was where do you get the 2D geometry, and where will those centerlines be? Your frame generator would have to account for various locations of CL. Top of steel, bottom of steel, center of beam, etc. Then you might have cases of needing to hold an inner clearance, out-to-out limit, etc.
I'm sure you've tackled those.
