BillboardCollection uniform color property

Hi,
I tried something out for a project I'm working on. I needed to be able to update the color of all the billboards in a single collection to the same color.
So I tried adding a uniform for color to the BillboardCollection and this is what I came up with.
I know this isn't ready to be merged as it needs tests and docs and such, but I just wanted to know what you guys think. Can this be helpful? Would you consider merging this?

Here is a cool example I created using this: http://cesiumperf-40397.onmodulus.net/

Thanks.