Most come with head rests, and you can get aftermarket ones for the ones that don't. Mine came with one, but I didn't like it so I changed it for another. What was killing me was holding my head at full extension upwards for long periods of time on my road bike.
The real speed demons are the two wheeled recumbents called high racers (a.k.a. "Stick bikes")
http://www.easystreetrecumbents.com/articles/wp-content/uploads/2010/06/sam_bikefit_example-300x225.jpg
and low racers.
http://www.bikeforest.com/m5_cromo_low_racer.jpg
Near road bike weight with a fraction of the frontal area. Those are what all the un-faired speed records are set on, and why they are banned from UCI races.
I just like the trikes more and mine is already plenty fast for our rides. The idea of an off road trike interests me, and there's a shop in Utah that customizes trikes that has a 90 speed big wheeled trike that would be pretty cool, or a fully suspended one. But I think the classic style bike is better for its nimbleness.