It wouldn't have to be like that, you could put a control device in to make the torque characteristic almost whatever you want...the situation I described is just the most extreme possible.

Gearing wouldn't really effect it that much. If you plot a graph of tractive force at the rear wheel (i.e. the force actually pushing the bike along) against vehicle speed, it's exactly the same shape as torque vs. engine speed, it just gets stretched one way or another depending on the gear ratios.

Similalrly if you had an electric motor that provided maximum torque at minimum speed, you'd always get maximum torque at minimum speed the gearing would just change the magnitude.