I need help with new Mac for my parents...

[sir pball]

10. You can neither buy nor virtualize OS X.

OS X 10.6 Snow Leopard was the last version available on full installation media - 10.7 Lion and 10.8 Mountain Lion can both be installed "clean" (i.e. on an empty hard drive as the first and only instance of an OS, not as an upgrade to an older version), but as of right now you need an existing 10.6+ installation as the Mac App Store is the only way to legally purchase Mountain Lion. Lion was available on a USB key, but Apple no longer offers that option for Mountain Lion.

It's a moot point anyway; virtualization is only licensed using VMWare on OS X 10.7 Lion or 10.8 Mountain Lion as a host and 10.5 Leopard Server or 10.6 Snow Leopard Server as a guest OS. Running OS X in any form, virtualized or not, on anything other than Apple hardware is strictly forbidden by Apple. Of course, if you were inclined to disregard SLA/EULAs, there's no technical problems with virtualizing 10.8. You can very easily find VMWare disk images with Mountain Lion already installed, all you have to do is plug and chug.

That being said, I would just have your parents buy a box and install a basic distro, then talk them through getting VNC up and running and go from there. It's what I've done with my dad and it worked flawlessly. Ideally, have the box shipped to you, get it completely set up, and then ship it back home, but that might be a little impractical.