Re: Picnic Tables & Benches...
In order to do what you want, you have to find a single item that is a picnic tables with benches.
Or we would need Turbine to replace the hook system with free form placement. I do not anticipate Turbine expending the resources for this kind of rewrite of the Asheron's Call housing system software. They would have done this enhancement in the initial implementation when they were porting to feature from their first game.
Unless stated otherwise, all content in this post is My Personal Opinion.