Is this kind of internal WCing possible?

well keep in mind that internal rads arent as good as if they are outside (hotter air inside) but internal is fine

Only problem i see with that is the top rad. Idk how ur gonna be able to only use 2 fans for the top. The spacing isnt set to be used like that

Pump is fine, generally only restraint is the res. should be above pump

Edit: also id leave out the single rad. and 3 + 2 is fine and the single will only cause a little more restriction and produce little performance gain

I have the 2 fans on top because thats how the case fans are lol

I could probably mod the case, but i don't really know what kind of power tools that would take... would it just take a normal power drill?

and i would put the res above the pump so that it could feed the pump by gravity its just kinda hard to show that in paint with a high sensitive mouse  

and w/o re-doing the entire image hehe

yea i understood that i was just saying that the pump placement was fine....make sure u get good parts (im sure u already kno that)

But yea the top....hmmm i mean ud need to cut a whole out which would be a....o god i forgot the name. DREMEL THATS IT thats what ud use theyre pretty cheap

As long as your T-line/fill port or reservoir is higher than your pump inlet, you should be fine. That is kind of a weird place for a res (referencing your diagram vs. the case pic) If you are really set on a res, consider a 5.25" bay res; I used one for a couple years and does what it is supposed to do.

Looking at that case, you might find it pretty cramped in there with what you are wanting to do...unless that case is deceptively large. I have a Gigabyte Aurora, which is pretty big tower...and I have my rads external...no way they would fit inside.

Edit: Also, how are you going to mount a 3x120mm res to a 2x120 mount at the top? That might require you making some kind of custom mount...and it might screw with your intended airflow. I would suggest some thick plexi and make you an adapter plate if you want to consider this...easy to cut, drill and is strong and light.

I know loop flow isn't a huge deal, but maybe consider running your pump straight to your CPU, then your top rad, then down to NB, GPU, etc.

pump > cpu > top rad > NB > gpu > rad 2 > res >