Here some examples of children’s scooters with a saddle, but no pedals… These are marketed by the German site Omni & Mehr on eBay and presented not only to allow the rehabilitation of people suffering from coordination and balance disorders, but also to mobilize the stationary. They are collapsible and are equipped with 20″ wheels, brakes front and back, and the prices vary between 210 and 325 Euros.
I can definitely see myself anon staggering around my rooms on one of these! More pics at the Trotinette e-Zine.
*BTW here’s the original Riddle of the Sphinx.