I successfully built it last night as well, although I didnt get much time to play with it as it was too late by the time i got it working.
I basically followed Dom's instructions, but here are some notes for anyone else who wants to try.
NFS booting is somewhat unreliable. I have to power cycle the pi to get it to work. Simply rebooting cause it to hang pretty much every time.
I also got the dbus error. As ntadej mentioned, adding "/opt/bcm-rootfs/usr/lib/dbus-1.0/include" to the includes in Make.include fixes it. Although it needs to be changed again after you do a "make clean".
I also get the TextureGL.cpp error. Dom's fix of adding "#define EGL_EGLEXT_PROTOTYPES" to Texture.h worked for me.
I had a problem i didn't see any one else mention. When running xbmc.bin, libshairport and libtiff could not be found but they were in the xbmc lib folder. I created a link in the /usr/local/lib folder and ran ldconfig and was then able to start xbmc.bin
I did all the build using the latest debian release.
My usb keyboard was acting strange, but it may be because it is pulling too much current, I will try another keyboard or stronger power supply.
I didn't actually try watching a video or playing any audio yet, but navigating all the menus wasn't too bad. A little laggy in some areas, and i think i remember the menu navigation sounds coming out of my rear surround speakers, but it was late so I could have been hallucinating.
By the way are we supposed to put new posts in the beta php forum, or here?