Depending on manufacture, model (style) and supplier, ball park you're looking at anywhere from mid $500's to over a thousand.........take your pick.

This toilet has been tagged as a Duravit Starck 2, it comes with several options, here's one Duravit 016009 One-Piece Elongated Wall-Mounted Toilet Washdown Model from Starck 2 Series
http://www.faucetdirect.com/duravit-016009-one-piece-elongated-wall-mounted-toilet-washdown-model-from-starck-2-series/p1112940
While the toilet costs around $500 to $600, the significant cost comes with what goes on behind the wall and the cost of installation.
If cost is a factor, you might prefer to go with a floor mounted toilet that is skirted. Skirted toilets also provide a sleek look at a much lower overall cost.
Here's a YouTube that describe what goes on behind the scenes of a wall-mounted toilet:

:) Rhoda