There is something similiar for the ipad http://algorithmicbotany.org/TreeSketch/
It uses same techniqe i guess.
i played with it some time - it was quite handy. But not yet got any real tree i had in mind out of it.
speedtree i was always interested in, but the pricing sheme prior to their architecture version was just insane.
I'll take a look at this. Thanks for the hint.