When The Truth About Cars spoke to the VP of product planning for Nissan North America, Pierre Loing, the smothering blanket of reality was thrown over the IDx duo: Nissan has no small, rear-wheel platform to build them on. At least, not one that it could make any money with. The 370Z is built on an architecture too big for the IDx, and sister company Renault only has small front-wheel-drive platforms. The idea of developing a chassis just for the IDx doesn't make any sense, as sales trends for the Scion FR-S and Subaru BRZ should show.
Will we see anything of the concepts in production guise, then? Loing said Nissan "may have some room" for a product with retro design cues and said to check back "in a few years" to get a final answer. But really, the answer appears to be, "No."