You might look into 'unattended installation' procedures. That way you can copy the installation folders (i386 and subfolders) to the recovery partition, create your unattended installation file parameters for loading network protocols, drivers, service packs/hotfixes, etc. Then you could either create a batch file to launch it in dos (I'd make that partition fat32), or create a shortcut to do a windows based installation. The real drawback here is the amount of time it will take to perfect the procedure for each machine... I think multiple licenses of Norton Ghost may turn out to be more cost effective. You may even have that bundled [Norton Ghost] with some of your hardware already, I know it comes with some motherboards.
I think the very best solution is the imaging solution. The only real difficulty with that would be needing a CD burner on each system imaged to write the image to - It would also eliminate the need to take up space on the hard drive.
Whatever you do it's not going to be easy, especially because they're preloaded machines. You'll need to keep good notes on what goes into them (new drivers, software revisions, service packs/hotfixes) if you choose to add those to your disaster recovery partition. It sounds like you may end up dumping everything onto that partition and just going folder to folder to reload the system - I would discourage that vehemently in favor of a simple imaging process because tech support will go insane otherwise.
