Not sure I follow your logic Miss Nancy, if the image you're trying to render won't because the shadow maps are too memory intensive then surely the only option is to render the shadows seperately and composite it in photoshop, the end result is exactly the same unless you have tweaked the shadows first in photoshop before compositing and flattening!

Of course you could go the multi-pass route and do it in smaller chunks but my preference is shadows and image seperate!

 

Injustice will be avenged.
Cofiwch Dryweryn.