Splitter code can be ripped out of the "kitchen sink" demo, it's relatively small. As I have said, the primary issue would be in modifying the tabbed UI to support either multiple tab sets or dynamically switch active tabs as editors gain/loose focus. Not sure how this would be made to look remotely elegant.
If you have time to experiment with this, feel free to. The current head revision has editors abstracted away into editors.* package instead of Ace sessions being tied to tabs, which might help something.