I spoke with Chris at SPC regarding a rental and he is already talking to a rental company. He also said they wont be making camber arms for the rear but it will be a bolt kit. This what he said:
We’re working with a rental company to trade an occasional alignment for occasional use of a car. Hopefully this will work out well. In the meantime, I have Kevin, who is going to try 350Z arms with 370Z balljoints some time next week. He is also verifying which rear camber/toe bolt kit (350Z or 370Z) is the correct one for the FX35. I can tell you that we will NOT be doing a camber arm for the rear of the vehicle, as the factory arm incorporates a shock mount, so our “EZ arm” style won’t work. Then again, we’ve learned that the camber is limited by toe anyway, so the bolt kit gives nearly as much adjustment as the arm anyway.