Imai did a superb 1/24 Mach 5, then issued a plethora of 'grade up' parts for it, so in the end it was possible to build it into a museum quality model. Then they upped the ante and released it in 'crystal', i. e. clear plastic, so it is possible to build one where you can see all the underbody details - if you can find that stuff.
I seem to remember that it is going to be reissued, but can't remember where I read it.
Rumour has it that Aoshima is going to release the movie version.