I found a Raspberry Pi LCD 3D model on here but this site is pretty good for that next idea you are looking for.
Yeggi is like meta search engine across thingiverse, youmagine, grabCAD and some other repositories. As search engines go its no google.
GrabCAD is one of my favourites as lots of the files are in proper CAD formats like Step that can actully model curves and stuff. It makes any kind of editing much easier than horid stl files.
I now see what you mean after clicking on a few of the links. STL files also don’t seem to import the correct size. I prefer STEP format for importing to my CAD system.
STL files dont include any units. By default most software assumes its in mm though and 95% of the time thats correct.