Im most of the way through the UVW mapping tutorial at fsdeveloper. Heres a gmax building I made and mapped textures using Lithunwrap:
Metal Building in Gmax
I made the texture sheet in GIMP (I dont have PS on this laptop):
Texture sheet
In Gmax I used booleans to cut out the recessed doors. The painting techniques I learned from Bill Womacks tutorials add very nice depth and shading.
This is just a "practice" building made based on a photo I saw online. Next steps are to finish lighting tutorials and then get back to modeling for my airport projects.