I'm a fucking ectomorph of the dead as well. 5"10 or 1m78.I might be wrong on this but from your pictures I think your body type is ectomorph. I have the same type. It's crappy and it sucks.
The problem with 'bulking up' is that you add 40/50 lbs of muscles on a small frame. Therefore, your heart can't really cope with all this muscle, therefore you most likely cut out cardio activities from your program. Aka, follow the routine of: eat a lot, almost no cardio => gain weight.
Congrats on eating a very healthy diet but be careful to end up with a functional body. No core strength means no strength in the real world. Assume you had to fight someone - do you think it matters one bit how much you can bench press or how big your biceps are ? If the goal is to just look good in the mirror, then congrats, you have achieved it.
I personally think the idea is to be able to use your body in a functional matter and end up looking like that, as a side-result, not as a goal.
When I started working out in September 2010 I was 123lbs. Picture that in your mind. My cardio was machine like even though I smoked. I could run for mothafucka DAYS and feed on thin air.
My goal was never to look like a body builder, just be more athletic and my #1 requirement was that everything gets bigger equal. Full body workout.
Right now I'm at 150pounds and it's still going up slowly. I'm still quite skinny, but I'm visibly built as fuck and I don't look like a body builder.
I did give up cardio like you say but lately I decided to give it another go and I was still fine after taking 30lbs. I even decided to keep running just to push myself and see where I was and a half hour later all was still good.
I'm not sure where you got that info from, personal experience maybe, but from my own experience, if you push your body naturally and steadily and don't aime for super fast results, there is no problem in maintaining good health and functionality. My hobbies involve physical activity and use of strength (sex and restoring old cars) and dude, I'm functionning like a motherfucker.