It looks like the release date for OpenBSD 4.7 has slipped a little, looks like it’s the middle of May

Dowloaded latest snapshot of 4.7 due for release in the next couple months, and seems stable enough for me on my internal sites

While there are no meta packages available in the OpenBSD repositories, it is possible to get a functioning XFCE4 Desktop with the following

export PKG_PATH=/pub/OpenBSD/4.6/packages//
pkg_add xfce-utils xfce4-panel xfce4-session xfdesktop xfwm4
pkg_add xfwm4-themes gtk-xfce-engine
pkg_add terminal orage notification-daemon-xfce ristretto mousepad xfce4-appfinder xfce4-mixer xfprint

This will give you a basic XFCE4 desktop, with some default themes

You can look in the ports collection for other XFCE4 Apps

cd /usr/ports/x11/xfce4 && make show=COMMENT

or of course, browse the xfce site