Ever seen those fancy exhibits in zoos and parks where they make fake rocks that look incredibly realistic? I found a link to a site with some very good info on the topic...there are many recipes and many techniques. http://pages.prodigy.net/airs/rocks/making.htm
One item discussed is making a large, boulder sized, hollow "rock" to hide something with...hmmmmm. wonder if such a "rock" would work to hide my very large, propane tank. Or maybe it would get too hot....
Scroll down past the sponsored web results to the web results and see what you can find. I'm not sure exactly what you're looking for, but one of these should have some good information.
Your post seems to be nice...but i want to tell you that i am not able to open that page here...My IE is blocking that page for some malicious script!!!