So right now I'm working on a compilation of Oblivion-style mods for Morrowind, things like Swift Casting in the MCP, Accurate Attack, Oblivion Style Interface, Oblivion Daedric Armor, Fast Travel, etc., and I'm trying to contact Westly for permission to use his Oblivion-Style Dark Brotherhood armor. But when I try to send him a message on the forums, it says he can't receive any new messages. Anyone know how I can get in touch with him?

You could try posting is his http://www.gamesas.com/topic/1458186-westlys-head-packs-and-headhair-replacers/page-5, in hopes that he's keeping an eye on it.

You could also try to PM him at GHF. Maybe his inbox isn't full there, and he'll get an email informing him of your PM.
http://www.fliggerty.com/phpBB3/viewtopic.php?f=129&t=4600 is a link to one of threads there, so you can find him easy.