Are there any plugins available to update the layout / available list of actions on the home screen once a user is logged in?
dashEE - is fully customizable ExpressionEngine control panel dashboard alternative.
Module comes with 8 default widgets but you also have the ability to develop your own tailored to your needs. In addition to developing your own stand along widgets you can also incorporate dashEE widgets into your existing custom EE modules instantly making your modules more usable by introducing new functionality right on the EE CP dashboard.
Zoo Flexible Admin is great for controlling and customizing what other member groups can see in admin control panel.
"Lets you fully customize the control panel menu per membergroup. Insert custom links, rename, re-order and remove menu items in order to create a more intuitive menu..."