Welcome to the forum.
Due to the geometry of the i-MiEV's suspension system, fitting larger wheels isn't easy. Putting 17 inch rims on would mean near zero tire sidewall. So far, it seems that the calibration for wheel speed can't be changed, so changing the tire circumference of either the front or rear tires will result in the disabling of regenerative brakes as well as throwing off the speedometer.
Just changing my rear tires from 175/60R15 to 175/55R15 resulted in a 4-5 MPH difference on my speedometer, as well as the loss of regenerative brakes, which uses the motor as a generator, slowing the car and putting some charge back into the battery.
It may be possible to get 16" rims, if you can find tires to fit with the same circumference as stock (tires are staggered sizes, so front is different from the rear).
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013
Solar-powered since 10/10/2013
"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015
2017 Bolt EV LT in Orange with QC - 7/31/2017
Driving electric since 2-21-2013.