So it turns out you can actually have the latest Apple UI fonts on Win 7. It was easier than I thought.
* download font dmg's from apple developer
* extract otf's using 7zip
* select the otf's and install
* copy the "aero" theme hier under WINDIR/Resources/Themes, so you get editable files (the originals are owned by trustedinstaller)
* rename the relevant theme files to follow the main "theme" file name
* edit the main theme file (config file) to address the display name
* set registry values under HKLM/Software/Microsoft/Windows NT/.../Fonts Segoe UI* to empty