For anyone attempting to do a Jumpstart install of Solaris x86 on a PowerEdge 1750, you may find the following info useful.
In installing Solaris 8 on a gaggle of 1750s, I found that the lsimptsl driver for the onboard LSI53C1030 scsi controller caused the Solaris installation program to crash spectacularly (followed by an immediate reboot) if a network boot image was used. The crash does not occur if the lsimptsl driver isn't loaded, and also does not occur if you boot from a local scsi cdrom instead of the network.
Upshot: It appears that the current incarnation of the lsimptsl driver somehow interferes with jumpstart/network booting (at least for PE 1750s). Installing from locally mounted Solaris CDs appears to work fine.