I just use "dumper/loader" scripts as I did in the old days with Sybase/UNIX, just converted to simple NT shell scripts, I do it every night to refresh our staging environments.

You can use sp_help_revlogin to extract logins and pws from source
- load databases via restore (I just restore via UNC paths that point to prod backups)
- fix users following each restore

What you want can be called "poor man's replication" and SQLBackupAndFTP + One-Click SQL Restore are exactly the programs to do it. Look here for more information: Is this tool for me - SqlBackupAndFTP General - Sql Backup & Script Generator