Assuming you are using blender, using array modifiers and mirror modifiers are your friend. If you are sneeky, got can get away with unwrapping only 1/6th to 1/3rd of the model. Also, using Unwrap --> project from view. Remember, as alpha is allowed, you can clone like the whole UV and have details as "decals" on top. I'll post some unwraps once I have got my mod pack 0.01 up. A good resource if I am honest is SOE's Player Studio, they have some 800 poly models to download for "reference", but they have some awesome ploy saving tricks and amazing UV efficiency tricks, just load them up and see how the map is done, will give you some great ideas. Also, how many posts before I am off 100% mod approval?