I am able to search my Tomboy notes using Synapse (and using a zeitgeist plugin), after following the instructions here: How do I get Synapse to search my Tomboy notes? My notes also appear in the Activity Journal.
Since both Synapse and the Dash rely on Zeitgeist data, why don't Tomboy notes also appear in the Unity Dash search results? Is there anything that can be done? (A similar question has been asked: Can I search tomboy notes with dash?)