Just a couple of points

Firstly there is no such thing as an

Active\active\active\passive cluster.

A cluster is either active\active or active\passive.

Secondly for dev and uat clusters, virtual is the way to go. I have used virtualisation (VMWare server and ESX server) for creating clusters using MSCS and more recently Veritas Cluster Server. Although with the current version of VCS it is somewhat tricky and troublesome, MSCS responds well in a virtual environment. Also, many people on this forum find my "Creating a virtual SQL Server cluster" guide very useful