I would like to draw my scripts and connect commands like blocks of functions (something similar to Yahoo Pipes). Does such an environment exist or do I have to develop it myself?
Not purely for Shell scripts but generic tools do exist which you can use to run your shell scripts. These tools are generally called workflow frameworks. One example is the Galaxy workflow framework: http://galaxyproject.org
You can easily create your own "shell-tool" and write arbitrary shell scripts and save them as your own boxes. Then, you specify the expected inputs and outputs and they become the noodles connecting these boxes. The interface is very similar to Yahoo pipes.
To know how to create your own tool see: https://wiki.galaxyproject.org/Admin/Tools/ToolConfigSyntax
There are many screencasts that can get you started. Galaxy itself is written in Python and is hackable with some familiarity.
All provide the same functionality with their own enhancements and features.