A forum member from Missouri that goes by the name of Jemmicat shared his design for a mikromedia Plus casing. It’s a simple but effective two-part solution that can fit a mikromedia plus along with a shield and click boards.
All you need to enclose your own mikromedia+ with this custom-designed casing is access to a 3D printer. Those are not exactly household items (yet), but try a service like 3Dhubs or makexyz to find one near you.
The casing has two pieces. The front board frames the display, while the backboard has a smaller cutout, just large enough to allow access to click boards connected to a shield. Two parts are joined together with 4–20 1/4" plastite screws.
You can download the SolidWorks files from Thingverse (a platform for sharing digital design files). A 3D preview is also available there. The files also include the main mikromedia board layout, as a reference to make it easier to modify the design if need be.
The files are free but keep in mind that Jemmicat published them under Creative Commons - Attribution - Non-Commercial license.
No luck finding a 3D printer? If you're creative you might find that (with a few modifications) you already have a suitable casing lying around the house. Like this reader who used a soap box to encase his RaspBerry Pi and RaspyPlay4 music player shows us. The aesthetics remind us of those iMac G3s from the late nineties.