I'm looking for a way to do this.
However I do that on a site. I needed for certain posts, always the same, to be presented in a different way. As the posts are always the same (those posts are always presented differently), I altered how the collection is built. It's a bit of a messy trick but it works.
So instead of having the following components for a news post:
I have this:
See where I'm going?
So in my template, I lay out the design for the first 3 components, I insure that if they are blank then nothing is displayed and there is no residual margin, paddings or white space, then underneath I layout the design for the -alt components.... Now all my posts look the same and all my -alt post look differently.
What you'll look for will come, I'm sure. May takes time, don't wait for it, find another way