RPi 1 (Model B) can be found here... http://www.thingiverse.com/thing:608169
RPi 1 (Model B+) and RPi 2 are the same, so the files currently uploaded for RPi 2 are correct.
RPi 3 top is the same as RPi 2. Only difference in the RPi 3 bottom is a small cutout for the SD card. I will upload this file.