Optimize Big window in Atlas

[echeg]

Hello everyone!
For a long time I used sliced sprites to create a windows, inside of which was tailed texture.

But in the new project the artists have drawn a huge number of windows similar to this:
https://dl.dropboxusercontent.com/u/1210840/backPop.png
If I insert a sprite in the atlas, 90% of the size will occupy an empty space. What makes me very sad.

I see video http://www.youtube.com/watch?v=fyIpbMMUOFw This is the best solution for these windows\sprites?
I have a lot of similar windows of various shapes. And slice each window + add alpha-channel on borders.It takes a lot of time...

[ArenMook]

Yes, slap your artists for being retarded and wasting texture memory, then covert them to sliced sprites, saving that memory and thus saving the day.