Module to manage password complexity

hi all,

I need in my enterprise to force users to choose a password hard to discover. All 'auth' / 'security' module are useless if password is just '1234'. So my questions are :
1/ It seems that there is no module to do that. It isn't ?
2/ Is server-env-tools the good place to do a Merge Proposal ?
3/ Do you know some lib in python to compute / define the complexity of a string ?
4/ Are there some people to work / review that kind of module ?

Quick blueprint of the module :
- create parameters to define a complexity level for password ;
- [optional / second step] set different complexity levels to users. (depending of access right) ; (Exemple : portal user : medium complexity ; accounting users : hard complexity)
- when user changes his password, force the user to tip a complex password ;
- [optional / Second step] when a user logs in, force the user to change his password if it is not complex enough ; (planned incompatility : auth_ldap).