Yes, this is possible. Might be more difficult than your expecting.

Remember this MPPT is boosting the panels output voltage, more commonly MPPT reduce voltage to match the battery.

The current in the Fet is ever changing with the inductor:
http://www.ngsir.netfirms.com/englishhtm/RL.htm

The current peak will be controlled by how long the Fet is on.
So as the on time is varied the current will vary.
Fets resistance changes over temperature... effect should be slow enough to not be a problem.
Fets on time is short 72khz, will require a sample and hold to capture reading.
Goal is to hit the Power Nee, current can peak higher than desired. Making control more difficult.

More may be required, my first look at doing it this way.
Over all an interesting possibility. Will have to think about it some more.