US Retailers won't have much to offer right now, as the car is very new. Give it a little time, and the car's aftermarket should grow significantly. The Tiida and Latio have been available in Japan for a while now, and there is a thriving aftermarket there.
Meanwhile, have a look at these threads concerning Versa aftermarket:
zerothread/178351
Some examples of items from the Tiida aftermarkethttp://forums.nicoclub.com/zerothread/152737http://forums.nicoclub.com/zerothread/186202http://forums.nicoclub.com/zerothread/186166