New version of sun virtualbox supports EFI. Is it possible now to install a Mac OS X from original dvd? (not a hackintosh). If yes, how exactly to configure EFI and what settings are required for Mac OS X guest install?
No, not yet. There are other issues where VirtualBox's emulation isn't quite good enough to run OS X, which have stopped most hackintosh distros working even though they work around the lack of EFI.
EFI is currently an experimental feature that only partially works on a few Linux and test bootable guests. It's definitely encouraging, though, after a long period of little progress towards virtualising OS X. Keep an eye on this topic for updates.