There are several tuner projects based on Arduino.? Here is one.
You can find schematics for almost all the major vendors out there.? The setup / hardware is basically all the same.
The hardware does not seem difficult.? The L match seems to be the most common.? I would use latching relays, so it could use very low power when not tuning, like the Elecraft T1 tuner.? The magic would be in the programming of the tuning subroutines.