Sims 3 Package Editor (ProjectK) For Mono by Kuree
It's not only a demonstration of the Sims 3 Package Library For Mono, but also a useful tool to edit package.
You can download it from CodePlex
Although there're detailed information about how to set up environment for DemoPE, I still want to address it here again.
1. For Windows Users: Please download .NET 4.0 Framework to use it.
2. For Mac Users: please download the latest Mono runtime(beta version).
Current Wrapper Support
Now it just supports modding, i.e. tuning or script modding. So if you need object creating or CAS creating support, please wait. 
Feel free to report bug.