Not with any currently available data, but when I was shopping, to get a workstation of similar specs was about 5g. Also, remember that the original launched with a chip that wasn't available in any other machine. It was I Lu available in low volume and apple snatched all of them up for their halo machine. Granted six months later yield was sufficient that all pc makers could get them. I don't mind the extra large case, it has great airflow, and its easy for me to get my gargantuan mitts in there when I need to do something.
So in other words, you can't support your claim.
The original did not launch with a chip that was not available in any other machine. Period. Bunk. Horse hockey.
About 8 months after launch, Apple offered a 3 GHz chip that was unique - because no other manufacturer wanted to use it. It was a special bin of the existing chip - but ran at 150 watts per chip. Other manufacturers passed on it, because Intel had a 3 GHz 120 watt chip in the pipeline a few months later. Since the cheese grater case was designed for the nuclear furnaces known by the name "PowerPC", Apple picked it up while everyone else waited for the new stepping which ran 3 GHz at the same wattage as the existing chips. It wasn't a matter of "sufficient yield", it was that a better chip arrived a few months after the thermonuclear 3.0 GHz chips, as clearly outlined in the Intel roadmap.
And the "$1000 cheaper" line has been pretty soundly debunked as well. That $1K cheaper line came from comparing a Mac "Pro" (2006) against a Dell PW 670. Every possible option seemed to be added to the top of the line Dell (1Kw power supply, 512MiB Quadro card vs the 256 MiB GeForce in the Mac "Pro",...). No Apple fan seemed bothered that the Dell had 6 internal drive slots and 7 PCI(/e) slots (vs 4 and 4 for the Mac "Pro"), nor that the Dell supported 64 GiB of RAM vs 16 GiB for the Mac "Pro". The Dell mid-tower PW470 was a closer match to the Mac "Pro" (2006) overall, but it was ignored because it didn't fit the agenda.
Please stop repeating nonsense.