It all comes down to the spin rate.
12x spins at 6 times the speed of a 2x drive, therefore carrying with it...
if we use the simple Kinetic energy =1/2 mv^2, we see a 144:4 ratio, or a 36 fold difference of kinetic energy in the disk when totally spun up.
AND this is at Blu ray's fastest. Note that Blu ray disks spin at constant angular velocity, which means that the outer layers require a much slower spin rate than the inner layers (and the outer layers carry much more info, so much more time is spent there)
Unless you can find a way to lessen the Kinetic energy, the sound doesn't go away.
Of course, there's also always the option of placing the 360 in a vacuum to take away the noise, but I wouldn't think that would be very nice in the cooling department.
So no, it's not an easy task at all.
Real viable options include
reducing the motor noise (which I expect them to be very good at already);
increasing sound insulation;
spinning the laser head in the other direction to decrease it to 6x from the disk + 6x from the laser head (which I havn't seen anyone try to do);
or spinning the whole console in the other direction (again, 6x+6x).
The first two are truely doable and I think are done by the manufacturing guys as they are obvious answers to the problem.
The third one is a design fiasco if you ask my opinion.
The last one makes for a nice firework show.
Go figure