Amp gauge shunt

In this age of electronics, why couldn't you use a clamp-on DC current sensor to measure the amps and then amplify the output to power a gauge needle. I'm not sure I could do it, but it doesn't seem like rocket science -- and good bye shunt resistor. This wouldn't cost very much and it is quite possible someone has already done this.

To answer the question below: They do make donut-type sensors to measure DC current. I'm not sure if they make the clamp-on (or split-core) type.