It may go by the names Blue Potato Bush, Paraguay Nightshade, Blue Lycianthes. I grew it for a few years by bringing it indoors for winter and putting outside for the summer. The only thing was that it lost it's leaves when brought indoors, regrew them over winter, then lost them again adjusting to the bright light of outside in spring. Nice plant though, and can be trained into a small shrub.

I know here the local nurseries sometimes carry it. Either in a larger pot as a small shrub or even in a small pot as a 'basket filler' type plant.