So after a little bit of tweaking, I can pop out multiple versions of rails at will now.
It all starts out with the super basic rail chunk with the minimum cutouts:
So I can add the cuts to make it more like a stock RTP rail (minus wings; none of my stuff has those stupid wings), plus a warp left notch:
Really, the rail I'm after is something like this uber ULE rail with the pim converted to a classic, and accepts a classic vertical ASA:
Just for giggles I did the Picatinny on a stock rail, roughly as described earlier; has clearance at the bottom so you could fit a plate over the whole deal. Again, I didn't draw the Picatinny, I straight instantiated it from another openscad library. I think the idea is a bit fruity and really interesting only as a CAD exercise:
And I went ahead and cut-and-pasted my ULE and the warp left cuts over to this module for funsies:
Pretty much any permutation between these is a cut-and-paste operation... in a text editor.
Seeing as it's all text (235 lines for everything combined), I went ahead and checked it all into a git repo, just in case.