SQL Server read-only SystemAdmin account

Is there a way to create a sysadmin like account with only read privilege's. I know that you can give a lot of grants to an account like view server state, view any definition, view any database etc, etc.. but still than this user will not always return the same info as the real SA user. In some system procedures there are checks implemented to see if you are sysadmin. It would be handy to have an account that can do all what you can do with the SA account except modifying anything. Is that possible?