Benjamin, I guess it is time to leave an area where you "own" and risk to try something new. You obviously have an understanding of the HL1 engine and how to bring it to its peak, but mapping for today's games requires far more IMHO. You are good at NS/ leading 
but if you really want to work in the industry, as you state, you will need to show the dedication to design and creation you are showing to PCWs etc.
You seem to have ambitions but you don't want to leave the areas you have mastered, because you would have to establish yourself again.
Modelling, 2D Art and understanding the underlying technology are no longer a plus, but seem to be a necessity for a decent map/level.
While I am not an experienced level designer (yet), my experience stems from the field of literature/academic studying, so don't take my comments the wrong way.
I respect what you achieved, but I am sure kleinluka and others are right, when they say you need AND can show a lot more.
BTW: I really like those nightwatch shots and the creative ideas about your NS map (light sources, mix of natural and human made surroundings).
well, what a thing to write such a post as the first one
mfg
Lance