Hi Signal1, I did a fair bit of videoing in my D1 and D2 and it was from a small mount that clipped into two of the vent slots at the front of the dash near the windscreen and tucked up into the grove in the dash just above the radio. I packed a large beach towel under the mount to keep it firmly in place.
I could fix it in place in about 30 seconds.
This is a video I took from the D1 6 years ago, along the Lions Road, from the tick gates down into Queensland.
As I used the same camera on a tripod, I regularly forgot to turn the stabiliser function on when using the camera in the Discos and this clip does not have it on but is still fairly stable.
Cheers.
http://www.youtube.com/watch?v=kG4x2Mx2KNk