RHEL does not install on a i586. Whitebox comes with a i586 kernel, etc.
If you are talking low end recycled lab machines with an extra stick of ram for this server, you may very well be on an i586.
I have a AMD K6-2 500 with 384 mb of ram that would make a nice lowend server for a classroom. It is currently running Whitebox, and it runs pretty well.