Oh, I don't know. Although the short wheelbase makes us all giggle I try to keep an open mind about these things.
In a recent article Mark Sanders commented
"This [the xbike] was a wonderful opportunity to do some fascinating, fundamental testing and bicycle research: solid urethane tyres, small wheels with and without suspension, hub centre steering, ultra short wheel bases, twisting front wheel drive transmissions, etc. Pictures HERE show some of the designs and testing – I learned that many of the so called 'bicycling facts' were in fact only 'de-facto' when used in context of cycle sport ... and not necessarily appropriate for everyday utility cycling."
BTW, Mark also mentions in the article that the thing which killed the xbike wasn't any kind of rideability problem, but the investment needed to tool up for state-of-the-art manufacture. It's funny how many grown men there are out there willing to spend thousands and thousands to ride around on plastic toys pretending to be Lance Armstrong, but have no interest when it comes to serious riding on a precisely engineered vehicle like the xbike: