This might be possible with e.g. installing ESX(i) on disk1, Windows on disk2 and modifying the boot loader.

However, since this seems to be a teat/lab system, so let me suggest two other solutions.

1.) (my preferred one) Install ESX(i) on your host system and Windows 2003 as a guest VM.

2.) Install Windows 2003 on the host system, install VMware Workstation 7 and run ESX(i) as a nested guest.

André