I am totally for this! Go Go GO!
Seriously though I have long dreamed of having an ST-21 in DCS. No one has ever brought it to life in any sim that I'm aware of, and what better place than DCS? I would definitely pay for something like this if it became available. Unfortunately as other people have said the 3d model would be the easy part, unless you were somehow able to take the flight model of the F-14B (as it was in say, DCS 2.5.5 or early 2.5.6 versions) and stick it on with some minor tweaks. Even at that, you still have to model the aircraft systems, which would not be easy. If there's enough interest in this then great, but there might not be.