I'll give you a few hints about what you can do with the most recent forms you've shown.
You see the flanges eminating ninety degrees from the sides? The vaguely trapezoidal shapes?
Use a fine-tooth saw and cut those off. They are wonderful scratchbuild material.
Same goes for the box-like section in the interior of the form in the second to last picture. That also is greebly goodness.
And of course, the downward haging flanges (the ones with the screw/bolt holes) in the same picture. would also be useful.
That said, I might even cut an internal section out along the raised structure lines.
Just a few thoughts from a guy who is still carving his way through the remnants of an office laserjet printer for raw materials.
When you scratchbuild/kitbash long enough, everything becomes a potential Lego piece itching to be set free from a printer, phone, tool, or household appliance