Using VMware across two sites

I have VMware esxi 4.1 cluster installed and running in 1 site with 2 physical hosts. They share two SANs. One SAN is directly attached and the other iscsc over ethernet.

We are about to add a second site with a high speed link between them. It will just be an extention of our private network. The plan is to take one of the hosts to the second site and still run as one cluster. Each site will have its own sub-net.

Can you see any possible problems with this set-up?

1. vCenter controlling the 2 hosts. Do / should I have a second linked vCenter at the remote site?
2. SAN will be shared via iscs over ethernet. What are the implications of this? Is there a better way at a resonible price...?
3. Virus protection using Trendmicro Deep Security - will it run in this type of structure?

I am also asking these questions on the vendors but would like to hear from the technicains that are in th ereal world and may have already done something like this. Any knowledge / information you can provide me with will be appreciated.

PS. I do plan to upgrade to VMware 5.5 . Is it best to do this first?

Thanks

Ron