WSO2 Identity Server is a open source entitlement engine which is based on the sunxacml. WSO2 Identity Server contains a nice XACML UI policy editor which can be easily used to create complex XACML policies.. I think it is better to try it by yourself. User don't want to have much knowledge on XACML to define those policies.
But still you want to define the attribute values by manual process. Also It has a PIP layer to plug any attribute finder module with it. Therefore you are able to find your attribute from any database, LDAP user store , web services and many more .... Also there are decision caching, policy caching and PIP level attribute caching to improve the performance.
You can download the WSO2 Identity Server from http://wso2.org and refer the implementation source code from https://svn.wso2.org/repos/wso2/trunk/carbon/components/identity.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.