FWIW...I converted my PIIA roof lights to HID, I think they're all metal/glass.



I don't know that HID's burn any hotter than halogen bulbs...

Halogen bulbs may even burn at a higher temp than HID's...

The kelvin "temp" associated with HID's is indicative of the spectrum of light they produce, not actual temp, otherwise, they'd melt anything (housing) that they were in.