If I may offer a suggestion, a desk reference like Everymac would be enriched by including a section just beneath the official OS support section [see below * as a generic example], where Everymac could report higher (and lower) OS versions which are demonstratively known by the Mac user community to run on a particular Mac model — replete with community-based links to static sites which can walk one through the steps on how one may do so on their own Mac. No, those community links aren’t commercial or sponsored, but they are instructive, informative, and are frequently peer-reviewed.
It might work to do:
Minimum Mac OS--blah blah
Maximum SUPPORTED Mac OS--blah blah
Maximum UNSUPPORTED Mac OS--blah blah
Maximum SUPPORTED Windows (for Intel Macs)--blah blah
Maximum UNSUPPORTED Windows (for Intel Macs)--blah blah
Just throwing stuff out and seeing what sticks here. For PowerPC Macs, you obviously would have N/A for Windows support, unless you really want to shoot the moon here and link Virtual PC.