And if your going to script that, you may aswell script a single label changing paintingmode...

And you are using mz, so why not?

Really you should switch to lua and check out my deskicons config in laserdock :D because all this stuff I have been through allready.

Also, there are no "default" images/icons used by xPC. Just the "window" or the label will still be created, just transparent as no "image" is configured.
Because paintingmode .none (the default) does not paint the window the same way (and is thus click through'able)
But that does not solve your problem.

In laserdock I have functions that figure out if the resource is image or icon and set the paintingmode evar for that label accordingly.

And remember the latest beta of xPC can handle jpeg's and gif's too ;)