These DC-DC converters are great, they are very cheap (~$3), and over 90% efficient.
I use them for powering my Raspberry Pis which I mount to a DIN rail on the end of my desk to keep them out of the way (see my RPi DIN Rail mount thingi).
After getting fed up with duct taping my DC converters to my desk I decided it was high time to design & print a DIN rail housing for them too...
I printed this at 0.15mm on my Up! Plus printer but it should print well at lower resolutions (0.2-0.3mm). The top section can be printed without a support structure but the base section will need one.