BOM Complete material list with links here: http://sonsts.de/blog/raspberry-pi-enclosure/
Raspberry Pi 3B - IoT FFT https://github.com/msonst/rpi-iot Real-time FFT via MQTT with one Raspberry PI Zero W + ADXL345 (high resolution 3-axis accelerometer) via SPI for data acquisition and one Raspberry Pi 3B+ with Node Red.
Raspberry Pi 3B - Backup https://github.com/msonst/rpi-backup Backs up several machines to a local drive via cron-scheduled rsync.
Raspberry Pi 3B - Nextcloud https://github.com/msonst/rpi-cloud Provides cloud features from your private network to your smartphone, Windows or Linux machine.
For RPI Zero please see https://www.cgtrader.com/3d-print-models/science/engineering/raspberry-pi-zero-w-enclosures