Been there done that, on my '07 Yukon XL Denali (4" plastic OE housings). Gonna try the HIDs in coming days (holiday break project), using my original heat-damaged housings to see if they 1) fit and 2) melt.
Will share results for sure!
I've seen potential permanent solutions, using
a glass H3 housing (with an LED halo!), but I dunno if an H3 HID bulb would fit (likely too long) into that housing. Plus, you'd have to mod the mounting brackets and also the wiring harness (connectors), but the connectors are no big deal...
If you find another alternative, please share it with us!