A bicycle built for none: Riderless bike helps researchers learn how balance rolls along
http://www.physorg.com/news/2011-04-bicycle-built-riderless-bike.html
Researchers explain why bicycles balance themselves
http://www.youtube.com/watch?v=_6l4N7_GiZM
The simulations that led to the building of the prototype shown on the videos have been made with the JBike6 software (freeware).
http://ruina.tam.cornell.edu/research/topics/bicycle_mechanics/JBike6_web_folder/index.htm
It would be interesting to enter the Strida parameters into that program and see if it is inherently stable or not.
I find the Strida very easy to balance at (very) low speed, but it get so nervous at high speed that I never ride faster than 35…38 km/h (downhill 
).
Who can drive his Strida hands off? I can’t. 
Well, on the website of the Technical University of Delft (Netherlands), one should find enough info (technical papers, thesis, movies) about bike stability as they are doing a lot of research on that subject. :
http://bicycle.tudelft.nl/schwab/Bicycle/index.htm
Well I even have difficulty to ride with one hand: I really need to be concentrated. 
Driving the Strida with one hand is easy for me. It just needed enough practice.
Hands off is a different topic, I can do this for a second on a smooth road, if the bike rolls without pedaling. But the push from the pedals is to much for the sensitive steering.
I can stand up on the Strida, too. 
But this is not really stable and I actually have less power.