Although SteadyState was never made to work with Windows 7 and it looks like it will no longer be developed after this year you can still get that Windows 7 functionality.
Microsoft has posted a whitepaper that shows you how to do it with current Windows 7 features and free tools from Microsoft:
This document is intended primarily for IT pros who configure shared-computer access in business environments, but partners who support shared-computer access in schools, libraries, and Internet cafes will also find the information useful.
The document set includes:
• Creating a Steady State by Using Microsoft Technologies (this document), which describes the native Windows 7 features and free tools from Microsoft that you can use to create a steady state on computers running Windows 7.
• Group Policy Settings for Creating a Steady State, which is a reference that describes Group Policy settings that you can use to configure computer and user settings and prevent users from changing those settings.
• The SteadyState Reference worksheet (.xlsx file), which you can use to look up and filter settings that this document and the reference describe. For example, you can quickly find information about settings that are related to Start Menu restrictions.