There was an article in SysAdmin in March 2002 that might have some good ideas. Sadly, it's not available online, but the blurb is below.
If you want I can probably mail or fax you a copy of the article, if it didn't get thrown out when I cleaned my car <g>).
Securing Public-Access Networks: Stopping the IP Thieves
Jones presents a solution to automating and securing the process of assigning IP addresses and configuring studentsí machines in a university environment.