Ian, i would venture to guess that most people who would be interested in a
ADA 1200/1500 setup, would be fine with a larger chassis... Granted going this route, those 2 products would have their own chassis, due to the nature of not being able to use "off the shelf" parts for you guys would add some additional cost for the different chassis.
But, i would guess that people looking for a product like that would be willing to pay the difference?
With the ADA1250/ADA1500 is comes down to a couple of issues beyond physical space:
Both of these amplifiers use a power supply "motherboard" that covers the entire bottom of the chassis. There are very high currents circulating on this PCB that would easily cause noise issues for the sensitive, low-level DSP.
There is also a lack of a suitable power supply for the DSP which would require an additional transformer and power supply PCB...yet more sources of noise and potential interference. The best bet from a performance standpoint is unfortunately separate chassis.
We can get away with the integrated system using the ADA1000 because of the different power supply configuration in that amplifier and the fact that we have the required power supply available.