I seriously suggest the new generation Mazda MX-5 aka the Miata.
I had a 2016 MX-5 C/S for a while, and I absolutely loved that car. It has a manual top, but it is absolutely effortless to operate the top. The car has good power, is fuel efficient if you baby it, and will tear through the canyons like it is on rails. If you can swing it I had the club sport, big breaks, bigger sways, Bilstiens on all corners. Sadly I sold it for a more commuter friendly car (something with an automatic
)
If it wasn't for the fact that I always wanted a Porsche at some point in my life, I would have purchased the newer MX-5
edit: just realized you need something with the possibility of a rear shelf.... My vote would be BMW, had an E46 325CiC (convertible) The car was heavy in the corners, but never hinted that it was about to loose grip. Decent power, and easy to work on. Again another great car of my past. (bought it on the cheap from the dealership I worked at, fixed some issues, and flipped it for profit a year later).