"Abdulmajid" (recorded in 1977; mixed and given a title in 1991) is not exactly about Iman, but it's dedicated to her.
You're right about the wedding song... There's a song on Black Tie White Noise called "The Wedding Song", which was written for Iman. "Angel for life", "Heaven's girl in a wedding gown", "She's not mine for eternity".... I think it's pretty safe to asume that "she" in this song is Iman.
Other songs about Iman? "Miracle Goodnight" perhaps. "A Big Hurt"?
"I got pissed but it's God who gave me this" -J Mascis, "Same Day"