Some people complain about Eddie being in the back, but I think this album cover is supposed to represent the band members. It only makes sense that Steve ,as the heart and soul of the band ,is represented by Eddie as the one in charge. I think the whole concept for the album art is about Maiden "soldiering on". As for the rest of the skeletons, I think the one riding on the tank with the cigarette is Dave(since he has been with steve almost from the beginning of Maiden). Adrian is casually walking next to the tank almost unoticed. Janick is upfront and in a goofy pose, and I think Nicko is the one with the bandana(looks kind of similar to a hat he wore in the 'Somewhere in Time' booklet. Which leaves Bruce as the hatless one.
And before you ask the question...actually I don't have a ton of time on my hands.