Since I've been setting up a lot of Cisco UCS blades lately I've been setting them up to boot from SAN to maintain the concept of stateless computing. I always get asked how you set up storage groups in an EMC array to accomodate boot from SAN. It's actually pretty easy. You will have one storage group for each blade in your environment that's going to boot from SAN. Then create a lun for each blade to boot from (probably 5-10GB). Within each storage group you'll have a server, the unique boot lun for that server, and then any shared luns that will be presented to your virtual environment.
It seems like a lot of overhead, but this allows you to specify the host lun ID as 0 for you boot lun which is a best practice when booting from SAN.
Keep in mind you can have the same luns in multiple storage groups, but you cannot have the same host in several storage groups (at least as of the EMC VNX series). But again, you'll have a different boot lun for each server.