This project started after an email conversation w/ MikeC when I bought a modded Seasonic PSU from him (great PSU, btw). This system is going into a sunroom and I was concerned about the PSU fan reving up, Mike suggested (
of course 
) a PSU duct and pointed me to numerous threads here on the subject.
Not wanting to use up a drive bay, I was going to go out the top of the box, but ARM beat me to the punch

. After reading Bluefront's comment on what would happen if the holes got covered up, I started thinking about going out the side -- not the door, but through the mobo tray. Going through the door would end up with a flimsy duct that would be hard to stabilize -- going through the other side let me attach to the mobo tray and keep everything in place.
Here's the finished product (apologize for the photos, they were taken with our office's poor excuse for a digital camera).
The duct was constructed out of cut up aluminum dryer vent that was pop-rivetd together and sealed with aluminum duct tape.
Here it is close up:
And the backside:
Close up:
Here it is with the door on:
And finally, the hole pattern:
So far, the PSU never revs up above 1000rpm (modded with a panaflo M1A) unless I put the intake side of the duct too close to a wall (I need it about 6" away). It's only gotten up to about 75F in the room so far, it will be interesting to see how it holds up to summer heat (90+ on hot days).
Currently, the only fans are a Papst 4412F/2GL running at about 9v (and a Papst 8412N/2GL (12v) on an SP94. Case temps in the low 30's and CPU in the low 50's at load (F@H). The only intake is through the front fan vent (and PSU duct), everything else is taped up.
As for the rest of the system specs:
3700BQE modded with side panel PSU duct
Seasonic Super Silencer 300 w/ M1BX
Acoustipack all around
Papst 4412F/2GL rear @ 1200rpm (my fan journey,
here)
Asus P4T533-c w/ P4 3.06 GHz
Thermalright SP94 w/ Papst 8412N/2GL @ 1450rpm
ATI AIW 8500 w/ Zalman ZM-NB32J heatsink
SB Audigy2 ZS soundcard
Promise Fastrak100 TX4
(4) 120GB Seagate 7200.7 as (2) RAID 0
TDK DVD burner
Floppy
I'm a little concerned about the HD's in this new case -- especially since the promise card won't allow me to monitor drive temps. I'm probably going put together a server out of old parts and put the RAID in it -- down in the basement where it is cooler. Then I think an SP80 in the BQE as the boot drive (on sorobothane -- didn't bother with the 7200.7's since they're moving anyway...).
All in all, the case is quiet -- a marked improvement over the 2600AMB that I had everything in. After I switch the drives, and get through some summer, I might add a front fan (but I don't want too).
Dave
EDIT to get the links working
EDIT added link to fan thread
EDIT added HD brand