Hi,
I'm sorry I can't commit to any timeframes to this. However, if you want to implement this yourself it should be really quite easy.
I can elaborate on my plans, as it may help you decide how to implement this. I have 2 plans for this -
1. Add a SpriteCollectionBuildComplete delegate, so that you can perform your own (global) post process at the end of it. This will be really flexible - you get the sprite collection + sprite collection data, and do with it what you wish.
2. A reflection based "plugin" system which can be added explicitly as a post process to a sprite collection. Eg. ETC'ify will be a post process that simply splits up your sprite collection textures into RGB and AAA.
I would implement this with #1, simply call your function from the end of tk2dSpriteCollectionBuilder.Rebuild
gen.spriteCollection.textures will contain the textures you will need to process, and .materials will contain the materials that will need to be patched up.