Hi, from few weeks I started to develop rails_panel: https://github.com/slawosz/rails_panel - readme describes how to start. It is early stage development now, but I would like to get some feedback, or (it would be so great!) contributors. Please look at the project and try to play with one of example app or create your own.
I know it has only basic features, but I belive that this architecture (simply inheritance) will allow to create highly customizable panel interface with many plugins (widgets).
So, please help! Every comment will be appriciated 
Sławosz @slawosz