Re: Roland TD4 KP for left handed
The TD KP4 setup guide shows that the cable loom determines where the hi-hat and kick pads have to be located relative to the module. You could probably get a lefty pedal arrangement by swinging each outer leg arm through 90 degrees wrt the central leg for a mirror image setup. The kick pad clamp might have to be flipped over but the other bits should mount OK.
It's just a 'left-field' idea but it could achieve what you want.