[eluser]Sumon[/eluser]
1. How would I load modules into the admin controller? Would I extend the Admin controller? Build a library that loads each plug-in? Etc.
=> I think you can include your modules using include "your_controller_name"; Moreover, from login information you know which modules you need. As such you can include those using include. Furthermore, you can access included module using ClassName::Function name.
2. What would be the easiest method of making the module blocks appear in the index page?
=> You can use switch control statement and load modules accordingly.
3. Where should I store everything?
=> All information should store in database and all view file / block (according to your design view) should be separated in different folders (like include, menu).
I am not quite sure these informations are helpful for you. I might not able to help you. In this is the case then i am so sorry.