I don't know anything about RHD Barchettas but I do know that you shouldnt give up on the idea of LHD without driving a car for an hour or so. You will never get used to the position of the car on the road, changing gear with your right hand, reduced visibility to the offside at slips etc. after a short test run but, once you do master these, and it doesn't take forever, the LHD makes driving even more fun. Hope you buy a Barchetta anyway though. All the best.
Steve