I have several suspects who could be behind the prolonged investigation ("Round up the usual suspects!"). I will not speculate about them here. But i will link to an interesting article, which points to IBM as the responsible company. Maureen O'Gara writes in Oracle-Sun: IBM Reportedly Behind Delay
Well, well, well, a little bird points to IBM as gumming up the works with the European Commission so Oracle and Sun canít close their deal.
In a bet i would put my money on IBM as well, albeit i would hedge some of the possible losses by betting some money on two other competitors of Oracle

More...