Won't be able to do it, but there's one that's been stewing in my head for a while. The inspiration was comparing the DeHavilland Gyron to the original P&W J58-P-2, from before it was adapted to the A-12 et al. The two engines are very similar in size, architecture, and power and I keep thinking of a Gyron Major that would be equivalent to the J58-P-20 for the Blackbird. So, my thought is to take a 1/48 Bristol T.188, fit it with 1/72 engine nacelles from a SR-71, and modify the cockpit to incorporate side by side 1/72 seats and panels. I'm thinking it would be labelled an R.188B to hide the program as an expanded research effort.