09-19-2011, 04:46 PM
In the past, the model-specific installers had a file embedded in the installer that verified compatibility of the target machine. Ditto for some drop-in upgrade disks that required presence of a previous version of OSX to run. In those cases, universalizing the installer involved making a disk image of the install disk and editing out or revising the pesky compatibility-check file and burning a copy of the edited installer. Doing this with your OS 10.6.6 installer would require figuring out what strategy that installer uses to accept/decline your proposed installation target.
Is it possible to run the new machine in target disk mode connected to your OS 10.6.6-compatible Mac Pro? If so, then you could install directly from the 10.6.6 installer via the Mac Pro. The Mac Pro will treat the iMac as an associated non-boot hard disk and not notice anything else about it. As long as the target disk installation is fully upgraded to 10.6.6, the iMac should work when you return to using the drive as the iMac boot disk.
Is it possible to run the new machine in target disk mode connected to your OS 10.6.6-compatible Mac Pro? If so, then you could install directly from the 10.6.6 installer via the Mac Pro. The Mac Pro will treat the iMac as an associated non-boot hard disk and not notice anything else about it. As long as the target disk installation is fully upgraded to 10.6.6, the iMac should work when you return to using the drive as the iMac boot disk.