Oracle RAC in LDOMs
According to this Oracle Website, Oracle RAC 10g is now supported within LDOMS. You need at least LDOMs in the 1.0.3 release. It isn´t supported as a hard partitioning, so it you still have to pay for the complete machine, but we are working on that. On the other hand keep in mind: A 4 node T5220 RAC cluster with 32 cores and 256 threads would be still eligible for Standard Edition as you count sockets for this edition, not cores.