Where can I find a graphical command shell?

Hotwire is an attempt to combine the power of the traditional command line interface with GUI elements. So it has a GUI side, and tries to be helpful in suggesting commands, and in showing you possible matches from your history. (While there are keyboard shortcuts to do this in bash and other shells, you have to know them ...)

You can use all your common system commands, but a number of key ones have new versions by default which use an object pipeline, and are displayed with a nice GUI view. In particular ls (aka dir) shows lists files and shows them in columns. You can sort by clicking on the column headers, double click on files to open, or double click on directories to move to that directory. The proc command allows you to right click on a process and one of the options is to kill it.

The object pipeline works in a similar way to Microsoft Powershell, allowing commands in the pipe to access object properties directly rather than having to do text processing to extract it.

Hotwire is cross platform (Linux, BSD, Windows, Mac), though it is at an early stage of development. To learn more, install (click on the link for your platform) and work through the simple getting started page.

If you don't like hotwire, you could also look at the list of related projects and ideas maintained on the hotwire wiki.

fish is a Unix shell that focuses on user-friendliness, such as by providing colored highlighting and extensive tab completion.

For a different kind of blend of textual and graphical interface, there's Quicksilver, as well as similar/inspired tools like Launchy, GNOME Do and ENSO.

Is this for Python in particular, or are you just interested in any command shell that has a GUI interface?

If the idea of piping file sizes into a pie chart interests you, you might try PowerGUI, a GUI layer on Microsoft's PowerShell command shell. PowerShell also lets you pipe data from commands into XML, CSV, and other formats that are understood by GUI programs.