For the led"s, I""ve created a transparent part which fit with the power symbol hole. This transparent part will capture all the 5 leds to the power symbol. So, the power button will be multicolor (there is differents leds) and will flash when for example the Raspberry Pi is searching/working on an usb port or other port.
I cut the case with a curve, because the inferior case are the front, the back and the back sides. So with a curve, I think, if you want to put two colors, like white on the top and grey on the back, the case will have a nicer look than with a case cut straight.
But I will draw two cases, one with a curve for the separation of the case and an other straight.