Have you looked at your BMW Dealer's stock of Previously Owned Vehicles? They may be able to find you a BMW Z-4 Coupe which is bigger, faster, better looking, and more expensive than the Z-3.
Depending on your price range and desired level of luxury, I would check out the new Nissan 370Z ($35k) or GT-R ($80k). Both are extremely nice sports cars with a lot of features for their respective price ranges. If it must be a BMW, look at the 135i.