There are 19 A330-300s on lease for Singapore Airlines. I presume they are still getting them (probably within 1 year atleast). They will most likely be in place until the 787-900 and A350 arrive in the next 4-5-6 years. So just an interim aircraft, probably with the same product as the Regional 777s, as They are starting to get rid of the 777-200s soon arent they?

EDIT: To be delivered between September 2008 and February 2009