Actually a difficult one to figure. Not too many manual Japanese convertibles out there with backseats.. 240SX (first car I owned

) and maybe 300ZX are the only recent ones that come to mind though both were not directly from a nissan factory and I'm not even sure if 300ZX roadsters were made in both the long and short wb variants.
For newer and going non japanese, you obviously have a couple choices but none would make me feel satisfied as a twin replacement!
I personally want a stick in a LC roadster