Make it table based ala mainhall.tbl. Otherwise there's not point to changing it - you'd just be locking us into a different HUD combination that nobody is used to.
The ability to add simple new guages and displays would be an incredibly useful addition too. Guages would obviously need to have an easily defined variable for display (Eg distance from a particular object, or along an axis, or hitpoints of a target, something like that.) Displays, on the other hand, would just need custom graphics, and be controlled by sexps - told to appear, disappear or flash.