Hi there!
You know many gamedev people (and not) use photoshop not only for editing assets. Somebody write export scripts for that to export all layers directly to engine or something like that.
Anyway there appears many rules how to name layers and check layer blending modes or cropping for canvas...
I do it a lot and many time spend to write little scripts to help myself not die in this routine. Now i just starting to collect all this functionally to one Photoshop PANEL. And i think its coming pretty handy.
So. You can see all features on page of this panel at http://cgidiot.com/tools/pspanel
It got lot of bugs for sure (course im no so programmer) but i will do fixes and adding some functionality in future, course i use it a lot myself .
http://cgidiot.com/tools/pspanel