couldn't you just design it with a small clue, such as an arrow, which would open a drop-down menu when rolled over (on a computer) or tapped on (on a touch device)?
I really, really like this idea as a solution to fix possible hidden rollovers usability issues. Like the best ideas it sounds obvious once you hear it. If it is well executed (I would imagine something clean and simple yet recognizable like a point within a circle) and when/where it does work, then - like you said - it's a solution that works for both touch and rollover, and that's exciting too.