Currently, we are using DNS round-robin based method for load-balancing the user traffic across 4 V10K.
We have created a Round-Robin DNS record and add all the P Interface Ip address in it. The user traffic is load-balanced all. There are many limitation in this as we can use traffic getting populated to a particular v10K most of the time. Traffic sent to the v10K server which is down as the DNS Cache still resolves to the dead v10K.
Websense to come up with their own version of Load-balancing ( like Microsoft ISA NLB) which will be take care of fail-over as well as Load-balancing.