Skylight bad idea on flat roof?
Alternative: Fiber optic sky light. You don't need to put the solar panel on the roof- it can be set anywhere with good light (the side of the house and roof are commonly used though). The optic cables could be routed anywhere (like under the house, through the wall, etc.).

I'm not really making a recommendation, but Huvco and Wasco/Parans came up first when I googled "fiber optic sky light".