It has been there for about 2 years and, so far as I am aware, has not flowered yet thought it appears to be in the process of forming a clump The leaves, which are triangular tongue shaped with white spots, have dark purple stems. Its height is currently about 17 ins. maximum
Haven't seen this particular one either, also think that is what it is - even has characteristic spotting of the leaves.
A couple of years ago U.K. garden centres were selling many new coloured forms of Zantedeschia, with pink,red, or purple etc spathes. There is one called Edge of Night, it looks pretty close to the pics, even down to the coloured leaf margins. We bought a couple,but lost them over winter outside. They do not seem to be as hardy as Zantedeschia aethiopica. They are very popular in the U.K.as cut flowers for weddings! http://www.terranovanurseries.com/wholesale/popups/zanen.html