At least the new HP BL460c G6 blade server is equipped with a Secure Digital (SD) slot on the side of the blade. HP VMware ESXi is supported to be installed on a SD memory card.
By installing ESXi on a SD card, SAS harddisks are not needed anymore. This will save some money on disks, and also SD memory is less likely to fail than hard disks.
Kingston Flash memory secure digital elite pro (50x) are supported. Such a card costs 8 euro! More information can be found in the ‘ VMware ESXi 4.0 from HP – ESXi Getting Started Guide (509678-003)’ This can be downloaded here.