Sorry, for questioning your request. I'd simply thought that it is better to work with the already given features than to wait for any of them.
But, in your case, the request is actually an easy one(means: you shouldn't have to wait to long for it.): to add a flag to none blocks and/or invisible blocks shouldn't be a problem.
And, it indeed adds an important adventure feature to GameStudio!
Quote:
I'd like an option to allow stencil shadows to be visible on either surfaces marked none or if it's possible on invisible blocks.
(I don't know what you were talking about shaders, I didn't say anything about them, and I, me, myself wasted the lot time of my project with them, and won't ever recommand to use them. [exept the ffp for environement mapping, and that one for multitexturing.] 
)
