I have the Giottos MT9360
and, in addition to the normal center column, it came with a very short center column that can be switched in easily. So I agree with Dennis, it should be pretty easy to replace with a very short column. The idea of the short column (according to the literature) was not for stability though, it was so that you could get the camera really low!
But, I am curious about your stability concerns. While attempting long exposures with ND filters, I have been finding that my shots are not as sharp as I would like. Recently I attempted a looping video of a waterfall that failed because, in the period of 30 seconds, the camera moved enough that I could not create a smooth splice. It was a bit breezy that day (and I was using my 70-200, but that and the 7D are well within the weight range of the MT9360 and the MH-1300
ball head that I use. When doing the looping video, the first thing I did was splice off the first and last 5 seconds thinking that that should eliminate any camera movement -- not so.