Currently there is no easier way to do it. When you say dynamic content I assume you are talking about a true-sized object. I see you mentioned checking the height on render, which again has been a solution before Famo.us makes this more accessible.
I have achieved dynamic content inside a sequentialLayout by creating a Custom View object that takes the same parameters as Surface. The view then creates a frontView that is visible and a backView that is not. If a size parameter comes in at [500,true] for example, backView will take the true-sizing and frontView will calculate the actual size in pixels. Then on resize, we can use backView as a sort of ruler, to do the dynamic sizing, while updates to the actual height in pixels are applied to frontView.
http://higherorderhuman.com/examples/dynamicContent.html
This sort of thing does seem harder than it should be, but that's because this behavior is a strength of the traditional box model. By throwing out the box model, we benefit in many other areas, but this is not one of them!