Wasn't someone a while ago going to look into getting some seats out of a totaled other Toyota, with comfy seats, and seeing if they could be easily put into the prius? Hopeing the mounting brackets were similar and the wiring harness for the airbags would be the same. Having owned and driven several Toyotas, I can say that it is a Prius specific issue. Maybe the seats from a Camry, Sienna, or Avalon?
And for me at least, I work with the thick part of the wedge to the back as I find the slope of the seat bottom too steep for my thigh comfort. But we are all shaped different.
Spike