hmm... the easiest thing to do may be hopping on craigslist and buying an older used mac mini and use that at home.
That's crazy... Why buy an old used mac when he has a brand new fast one with a warranty and hardware like thunderbolt, Built in W-fi & Bluetooth., .... he just needs the older OS so as not to buy all new software....
20 bucks on craigslist....
I think some of the new stuff on new Macs will not work with the old OS. My boos tried to install 10.4 on the new Macs we got few months ago and it would not allow him to install older OS on new Mac.
I know that some RIP software on the Imaging dept at printing Co. where I work will not run on Snow Leopard and the new Mac will not take the older OS (10.4). Also, that lady could not hook up the old video card because it was not compatible with the new OS, there was some issues with the hook up of the second monitor. On mine, everything works fine
And yes, you can not install anything older that CS3 on new Lion OS.