You could use spare screenspace for an oldschool GUI block, the minimap (pls no AREA/VIEW switch, lol), compass, action buttons etc. Then again, map can just hang alone in, say, upper left corner, and basic NSEW compass widget at middle top edge. The bottom can be used for the row of buttons with standart actions GB-style - camp, search, cast, what have you (better as a solid block than a bunch of disconnected buttons). With this resolution, you could probably fit them all at once without the submenus
Or make them pop up on hover the www-style. As for message panel, you could either do independent popup windows like Realms of Arkania, or have a fixed text console which pops up at the bottom of the screen when there is something to tell (and either disappears when there is no text to show, or is permanent but can be minimized by player).