There's a new pharma company called 'Dermira' which seems to be focusing on sebum reducing agents. Of course their target market is acne because it's such a huge market but it can benefit us oilies too!
Their most advanced agent is called 'lemuteporfin' which when used with light therapy reduces the size of sebaceous glands. Unfortunately it's not a permanent solution - you'd have to keep going back to keep your oil down - but it sounds promising.
Here's their web site:
And here's the clinical trial: