I just recently purchased a G5 and have a custom made, sound proofed Iso desk that I put it in.
The G5 is a really big machine and barely fits inside the desk with hardly an inch to spare in the rear and an front. Ventilation is an issue but fortunately there are two holes drilled on the side of the desk, on the left side of the G5, for muffin fans. Exhaust for the hot air is a different story.
I am seriously considering cutting some holes in the back of the Iso desk and running some ventilation tubing to the outside of the desk and just using the muffin fans for fresh air intake. I've heard this can make a huge improvement int the performance of the computer. The only thing I'm concerned about (other than cosmetics) is noise coming from the exposed exhaust fans.
Has anyone had experience keeping their G5 cool in an iso desk or box? How do they do it with the other kinds of professional computer iso boxes? I'll include some pics tomorrow.
First of all, depending on the exact G5 model and types of hd's installed, they're actually very, very quiet. My G5 is almost noiseless.
You have to be really cautious about an iso box for the G5, it might actually prohibit ventilation up to a point where it will overheat instead and this will in turn decrease performance (clicks and weird stuff) and fans will start spinning up.
Using external in/outtake of air can sometimes mess up the internal ventilation in the G5, causing it to actually worsen matters, I've experienced this myself.