Did you check out SKU 1402605?

It's a "special" eGo-T board with:

With LED indicator for battery voltage, click the button and the light will on: high--blue, medium--purple, low--red

It doesn't have the variable voltage to click through and has a basic voltage indicator instead for the battery. It sounds better than this board for what you are doing.

I am toying with the idea of optically piping the LED light with a strip of silicone, the box won't be transparent.

That's some spooky action if the short protection is functioning. :P

Edit: That diagram is definitely for a plastic case. ;)