I got a few PM's about the process of putting in the bottom drain, so I'll explain it here so everyone can see:
 
First, get acquainted with the fillport/drainport that I used:
http://www.sidewindercomputers.com/big14shsicat.html
As you can see, it's designed to go into a hole that is larger than the internal threading and smaller than the locking collar. 
I've measured this diameter to be roughly 3/4". 
So I bought a drill-bit in that size from my local hardware store. Ask a in-store helper if you're unsure on what to buy. Buy some Ear and Eye Protection. This drilling will be very loud and metal shavings will fly everywhere!
 
Tools:
Ear and Eye Protection ( I cannot stress this enough! )
Power-Drill (preferably a corded drill with a leveling sight)
3/4" drill bit
Clamps
Wood Blocks
1/4" or 1/8" bit
Metal File
 
First the prep:
My case bottom was made out of Aluminum, a very soft metal. The best way to prep for this is to prop the surface against a sturdy block of wood. Use some clamps if at all possible. The biggest problem you'll face is your target moving on you. The best suggestion I have is to find a piece of scrap metal and practice first, rather than going straight to drilling holes in your case. (Old case, anybody?) Your goal during practice is to drill a hole precisely where you want, without having the drill travel away from your target.
 
Drill a guide hole:
I determined the center that I wanted for my drainport, then drilled a small guide hole using a 1/8" bit. This basically keeps the larger bit from traveling while drilling the 3/4" hole. The important thing is to go SLOW and do not PRESS. Going fast will heat up the aluminum and may melt the sections you are cutting, causing it to warp, while pressing may bend your surface.
 
Drill the final hole:
Get those blocks out clamp everything down. Don't press the drill bit hard into the metal. Apply just enough pressure to let the drill bit do the work. USE A LOW RPM. For me, a hole of this size takes about 5 minutes of gentle drilling. "Slow and steady wins the race."
 
Deburr:
Get a metal file out and remove any burrs from the edge of the hole.
You can be fairly aggressive with the file as 3/4" is slightly small for the drain port. You will need to file ever-so-slightly to get the drain to fit. [For my top port, I needed a Dremel to clean both layers of aluminum.]
 
Clean-up:
Grab an air-compressor/canned air and a big vacuum. Blow-out and vacuum every corner of your case and get all those metal-filings out. We don't want one piece left to short out our parts!
 
I really should've posted pictures whole process, but hopefully this will suffice. Thanks for all the comments, everyone. Glad you like my work.
 

Great info and sweet setup! 

I use a prick punch (lol) and a hammer to make a guide hole when doing any kind of drilling like that, it helps immensely with bit-walking.

PM_DMNKLR

I use a prick punch (lol) and a hammer to make a guide hole when doing any kind of drilling like that, it helps immensely with bit-walking.

 
All a matter of personal preference. But, a while back when I tried that (on my Northwood 3.0 GHz PIV build ) I popped a rivet. I agree, if you can pull off the punch, travel is practically a non-issue.
 

hething 

You just made me want a SR-2 rig!  

 
 

 

Naw just a really cheap case. . I was surprised when it happened. Piece of junk fell apart on me :/ And yes, it was a prick punch. But come to think of it, that one was steel, not aluminum.

Update! 



 
Yes, I managed to fit a third rad in:
TA120.2 in the top and bottom.
PA140.3 in the front.
 
Drilling the holes for the bottom rad was...fun.
 
I had intended to tax my machine exclusively CPUs only or GPUs only. Problem was...those GTX590's are really toasty! (DUH) My idle CPU temps were pathetic to say the least. ~45C. And if I chose to game for a few hours, even without taxing the CPUs, I'd average nearly 60C! At <10% CPU usage!
 
I felt that having the 590's in parallel in such a long loop really killed my flow. I learned that parallel is only a good option if they have a dedicated loop--parallel works against me in long loops. 
 
Third rad in, and now my temps are great!
GPUs and CPUs now idle at 35C.
CPU temps during gaming hovers around 40C.
Folding on the entire system w/ 5GPUs and 22 Threads:
CPU's 60C
GPU's 45C

 
IMO, I managed to really improve the overall look of the tubing as well. Designing the loop was a little easier this time with the GPUs exhausting towards the bottom--it opened up a lot of space.
 
Alright, no more rebuilds for a while. It took me 5 years to save enough money to finish this one off.
 
Thanks for watching.

I think it' great.
this is a pro work

very, very nice work.
 

Very nice, I like the "library" look of your last image..

Your 3D mark 06 looks pretty low , can you bench it again.
because I got 14200 with single e5603 and gtx 465.
your system should score more than 40000 for sure.

new2019

Your 3D mark 06 looks pretty low , can you bench it again.
because I got 14200 with single e5603 and gtx 465.
your system should score more than 40000 for sure.

 
Alright, I'll bite. I haven't re-run the benchmark since BIOS-modding my cards.
 
I have to take myself back a bit considering '06 came out right around when my 7800GTX's were getting replaced by the 8800-series and this benchmark smoked my old machine. But, then again, the development period for '06 was before the advent of (consumer available) Quad-SLI and 3-Way was in its infancy. This is only confirmed by what I see from my reruns:
 
http://3dmark.com/3dm06/16625213 28032 - Quad-SLI
http://3dmark.com/3dm06/16625225 27490 - 590 (In SLI-mode)
 
Yes, that's right folks, I get fewer futuremark points going quad than the original MSRP of a EVGA 590 Hydrocopper.
 
In other news...
Since my chips have aged, they no longer handle the turbo as well as they used to--I was starting to get random 124 BSOD's with balanced power profiles. Most likely this was due to a random x23 multiplier popping up for a single-threaded app. After several days of tweaking I finally managed a 200 bclk so I could disable turbo and still manage 4.0 GHz. Memory timings had to be loosened to run at 2000MHz, but ahh what the heck, Adobe Premier loves the extra throughput.
 
Thanks again for the comments / views everyone, even if "Cecilia" is starting to show her age.