I really like tinkeringtech's enclosure for PocketBeagle and made a couple revisions. There's a cutout for the CPU in the bot.
BeagleBone Black Heatsink Enclosure
DIN Rail mounting enclosure for BeagleBone Black
A portable project case that you can put in your bag and take with you.
Unibody Aluminum Case for BeagleBone Black being sold by Adafruit
Aluminum case for BeagleBone Black on sale from Adafruit
Clear plastic BeagleBone Black enclosure available from Sparkfun.
Enclosure for BeagleBone Black
keep those birdies safe