I'm not positive, but I'm guessing the network diagram in that blog post is using one or more stencils from
Graffletopia. You can download any of those stencils and install them, as well - the built-in ones aren't the only ones.
Does that help at all? Haven't used ConceptDraw, so I really can't comment much on it. (Do the various "flavors" have actual functional differences, or do they just have different stencil libraries?)
Oh, and if you
email us, we can extend your trial period. Obviously, we can't do that indefinitely, but if someone needs a bit more time to decide if they need the app, we're not opposed to that. :-)