a single piece of sheet metal could make that entire top part, roof flashing material might be too thin unless you have some sort of structure under it. clip out the sides and cut vents, a couple pipes along the edges to hold the strength, distance, and to keep that curve. What's inside the guts however probably standard reflector stuff.
Do able without out TOO fancy of tools or anything, however being as you can get a DE pendant from someplace like HelloLights for $35 that's very simplistic I don't know if I'd bother with that.