Just an FYI, there have been some changes to this document.
In the past, there were issues around the use of NIC teaming for the heartbeat (private) network in clustering. In Windows Server 2008, there have been some changes. The update to KB 254101 states that NIC teaming is fully supported for Windows Server 2008 and Windows Server 2008 R2 Failover Clustering.
This is a nice change and has been requested by several people over the years. Personally, if I want to provide fault tolerance for the private network, I would just create multiple private networks, but that is just my preference. Your mileage may vary.