Is there any free multiuser self hosted Linux virtual lab environment?

Last year I had to teach Linux (LPIC-1) as a professional course to a group of engineering students that had never used a Linux system before. I am to take the course again and I am looking for a solution to overcome the challenge of limited access to Linux systems by the students which hampered their learning. Is there any opensource/free multiuser Linux virtual lab solution that can be self hosted on the local intranet and won't require internet access? Something similar to Webminal http://www.webminal.org or Tuxlab http://tuxlab.org that students can connect to remotely or via a web browser. Also suggestions for a project based LPIC-1 curriculum will be appreciated.