Just some quick build notes:  The PCB layout was designed specifically to fit the Sparkfun WIG-08601 case.  I choose the knob (Sparkfun, COM-10001) because it's tall enough to extend past the top of the case from the PCB.

The remaining issue was coming up with the cut-outs.  There's an opening on the bottom of the case, so USB and Power are there.  This works well with wall mounting, since power and your computer are likely below the level of the controller.

For the front facing items (LCD display, knob, reset button (on mbed), photocell) I had to cut openings in the case.

I did not have good tools for this.  I had one brute-force tool, a Dremel. The Dremel cuts through the plastic easily, but it leaves a jagged, melty mess behind, making it very difficult to do precision work.  Sort of like trying to do fine cabinetry with a chainsaw.

So I hacked out openings large enough for the various front-facing elements, then printed out a nice faceplate on heavy photo paper to cover up the mess.  The faceplate was designed in Adobe Illustrator.  I made a scan of the Sparkfun case, and used that as a template for designing the faceplate.  This works surprisingly well.

The finished controller mounts on the wall to control a string of about 60 Curilights in our kitchen dining area.  It mounts easily with foam mounting tape; the unit is light enough that other mounting hardware wasn't necessary.