I've seen a few variations to structures for topsy turvy cakes and even ones like this one: http://2.bp.blogspot.com/_sWZ19d8sKJA/TH5VoBihljI/AAAAAAAAA6M/lJNZ7EhotKc/s400/copy+MG_3561.JPG

I think the end result is pretty cool but can't figure out how the cake actually stays in place? I mean if you made something like this and put the cake on it the only way it would 'stay' is if you added each layer one at a time and put the center pole up inside the middle of the cake right? but if the cake is really soft (which mine usually are - i.e. light and fluffy) it may not hold it's own weight. so is there any other way? or do you need to use a more dense cake?

That is Bronwen Weber and Francois Long's Caddy Wampus stand

http://www.caljavaonline.com/cakestudy1.htm

The center post and connectors support each layer separately - there is no weight from the tier above. Any cake would work with this stand - stacked one tier at a time. There are several posts here on CC about experiences with this stand. Great look!