I realise I didn't say before, but with ffmpeg12[vdpau] I get no video, but do get audio.
Now, using onboard video, I get a picture with both
mplayer The\ Simpsons.mpg -vo vdpau -vc ffh264 > onboard_ffh264.txt
mplayer The\ Simpsons.mpg -vo vdpau -vc ffh264vdpau > onboard_ffh264vdpau.txt
Re mplayer version, I apt-get source'd version 2:1.0-svn29095-x264-vdpau-0ubuntu1, and recompiled with --enable-debug. I have Jean-Yves Avenard's repo activated. If it helps, I could try to fix this.
It might be worth pointing out that I plan to use vdpau for mythtv, which I have running at present with software decoding. It is also unable to use vdpau, but i thought it would be a good idea to at least get it working in mplayer first.
I have uploaded a sample of the video to http://www.aaatos.net/videos/The_Simpsons_Short.mpg