Really? Go to any BMW dealership and you can easily get a Z4 of your choice. Go to a Porsche dealership and good luck walking out with a GT car. And if you are talking about the Mk4 then sure I'd agree but pretty sure both the Mk5 and new Z4 being a shared platform will be readily available. Maybe not initially as in case with the Mk5 as it's the "new hotness" but give it 6 months to a year and you will see them everywhere.