I took a trip to another big hardware store, and found myself a Pet Rock! I've updated the project photo to show what it looks like before it receives its WiFi conversion.

I also bought a spare, because probing the innards of rocks could cause distress.....

The rock, which was originally waterproof, has a nice switch on the bottom that I could use to turn the rock on and off. Instead of replacing the original battery holder...

I may just end up using the empty housing and mounting the replacement battery, VoCore module, and power supply circuit on top of it, inside the rock.

The LED light will probably be replaced, as will the original tiny solar panel. The charging circuit is this rock looks far better than the shed light, except it is for a Ni-Mh battery. It has a single through hole resistor, and something under a blob of epoxy.

I had thoughts of using the reflector from the LED as a sunlight concentrator.......or I could remove it completely and just leave the clear cover so you can see inside the rock? Thoughts? I could connect a red LED to one of the GPIO's and do something there? RedRock?