I actually have a version of the Shadow World. But its not nearly as foul as Ravenloft. My PCs haven't expressed much interest in it though, so I've never taken the time to expand it greatly. I even have a nifty verse for a springboard when I work on the SW:

Job 38:17
"Have the gates of death been shown to you? Have you seen the gates of the shadow of death?"

I'm not sure if your familiar with the Bible, but its a portion where Job questions God and his sovereignty. God replies with a series of questions rather than answers. This was one of them. The translation to the campaign is that God knows it exists, but that humans have yet to comprehend it.