I have put some thought into just how to have the dowel axis along the x. It would have to be turned by the y motor. That is, the dowel would have to roll left and right following the carriage against rails above the dowel (not on the sandpaper belts). These rails would have to be at the ends of the dowel which may be far outside the machine. Seems to me to be very difficult, and, it would be very hard on the y motor.

I think that four (or more) sided carves may be the way to go with table legs.