So if the i30 is "fly by wire" with the accelerator pedal operating a potentiometer to send a signal to the ECU. What's to stop you from fitting the same resistance potentiometer mounted to the dash and connected to the same cable as the accelerator via an interposing relay that switches back to the accelerator pedal when the brake is pressed (It's only 3 wires). To activate you press a momentary button that pulls the relay in, the relay then holds itself in until the brake switch breaks the circuit - Any electrician will know what I'm talking about. I don't know what the ECU will think at the point where the relay is between foot operation and hand operation though.
Sure it isn't cruise control - but it makes you think................    ONLY THINK ABOUT THIS ONE TOO, DON"T TRY IT ...........  like I said in the Topic title "madness I know"

I had '67 Fiat that had a hand accelerator mounted right beside the choke. Niether were particularly easy to reach being sort of below the dashboard and above a parcel shelf. They were both virtually identical too so it was a potential for confusion.

I used it as a poor man's cruise as I assume was its purpose and it was surprisingly useful on a highway drive. It did not disconnect unless you pushed it back in. One got used to it.

[asathorny]

So if the i30 is "fly by wire" with the accelerator pedal operating a potentiometer to send a signal to the ECU. What's to stop you from fitting the same resistance potentiometer mounted to the dash and connected to the same cable as the accelerator via an interposing relay that switches back to the accelerator pedal when the brake is pressed (It's only 3 wires). To activate you press a momentary button that pulls the relay in, the relay then holds itself in until the brake switch breaks the circuit - Any electrician will know what I'm talking about. I don't know what the ECU will think at the point where the relay is between foot operation and hand operation though.
Sure it isn't cruise control - but it makes you think................    ONLY THINK ABOUT THIS ONE TOO, DON"T TRY IT ...........  like I said in the Topic title "madness I know"

I imagine that what you have posited here would be essential for some of our disabled cousins....   in fact, it may have already been done