yes similar to that i'll try to upload what i used to do and the version phoenix said.


in the second one look at the top left window view... im chamfering the edge then i would pick the end vertices and chamfer them then delete the inner lines and extrude the polygon then extrude-bevel again to get the desired look... then apply smoothing groups to the polygons except for the end 3 and the top one.
ps: yes you can do what you do ie extrude down on the top poly to make the "trough" effect
its how i do mine... hope its clearer to you than i fear this post is lol