You did seem surprised that someone has figured out how to install Windows on a Mac, and I though I would point out that Apple knows about that, and has provided tools as a standard install in OS X to simplify that, and it's been in use for more than 5 years. Some folks use the same tool for a quick start on installing other OSes, usually some flavor of Linux. I would think that Solaris would not be that much different to install. In the end, there's not huge differences in the motherboard/chipsets used by Apple, compared to other good quality current computers.
Some will point out that Apple hardware tends to be slightly behind 'cutting edge' in some ways. But, I think that should make the process for installing Solaris simpler when you don't have to figure this out on your own (someone else has likely done Solaris on your specific model, and posted some helps on the 'net, somewhere)
Serendipity is a lucky guess !