We have implemented a HA solution in a VM cloud. Total nine big boxes forms the VM (2 dedicated) for the SQL HA cluster. (Other VMs are runing 40+ servers)

SQL Sever 2005 is installed on these dedicated VM with active-passive configuration. So effectively both the nodes are sharing the disks. We have also implemented a DR solution using Database mirroring to a different site to provide more HA (Our DR site link is bit slow now, so we have used High Perf - Async - Manual failover and expecting a high speed connectivity soon. And it will be changed to High Perf - Sync - Automatic failover with a witness server).

We are expecting SQL should be up and running within few seconds of any failure (disk/network cards/CPU)