The Swiss-made RaXibo Hand-Tret-Velo comes with a pedaling system built into the handlebars so that you can use the strength in your arms as well as your legs. The only downside that I can see is that it would make texting while riding much harder.
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Apart from, you know, the whole "can't steer for shit" aspect. It's ALMOST as dumb as a Segway. Almost.