I want to make a tall, skinny cake, similar to the one here:

http://www.iconicaphotography.com/blog/wp-content/uploads/2011/03/tall-skinny-wedding-cake.jpg

I am trying to figure out the dimensions and how to give it the "tall" look. I figure the cake itself is going to be 4 layers, and I was thinking of putting a thicker foamboard (1") on the base (underneath the fondant) to give it the additional height.

But what should the tier diameters be? 6-8-10-12? Or should I go with a 6-7-8-9? Will that be too pyramid-like?

Thanks!

The picture, to me, looks like a 2-inch difference between the tiers. The addition of the 4-inch tier on top makes it look skinnier, I think, so if I were doing that style with 4 tiers, I would do 10-8-6-4. With only a 1-inch difference between tiers, it might look a little bit like a pyramid once you get the fondant and decorations on because that only leaves 1/2 inch around. I like your idea of a thicker base to give it additional height.

For reference on the size, the "rose cake" in my gallery is 10-8-6-4, but with spacers in between the tiers.

I think the cake in the picture is 4-6-8-10-12 x 4".