I have just finished uploading a model of the JN-2 hull:
https://www.shapeways.com/product/CKRCE4TB5/1-100-jn-2-sab-original-hull
The JN-2 SAB is a larger and slower but much more powerful development of the JN-1 SAU.
This vehicle, like the JN-1, is designed to bring very heavy firepower to the front lines, rather than keeping a safe distance as traditional artillery must. Unlike the JN-1, however, the JN-2 is meant to remain largely in one place, usually taking a hull-down position behind a redoubt. From there, it will fire "broadsides," as a battleship would:
The JN-2 SAB is usually supported by a second vehicle, called the JN-2 TO. I haven't made it yet, and I'm not sure whether to call it the TO or TS. One means "weapons transport," and the other means "shell transport." If I decide that the support vehicle will carry weapons and supplies for all the soldiers in the redoubt, then I will use the former designation. If it is to carry only shells for the SAB, then I'll use the latter. Or, perhaps, I'll make two versions and avoid the problem entirely.
The support vehicle is not the only variant I have in my mind. The first is already under construction:
This is the mid-production variant of the vehicle. As you can see, it has different running gear (looks almost exactly like the Soviet T-35, in fact). I will go into the reasons for that when I have all the vehicles finished and I discuss them on my Wordpress blog, but the short story is that the factories were unable to get the proper alloys to make torsion bars, so they put a different suspension on the tank. Below is a comparison:
Tomorrow, I will probably finish putting the details on the mid-production variant (can't use the same side hatches with the bogies in the way), and release it in my shop. After that, I will work on the support vehicles, of which there will be either two or four (because they also have both types of suspensions). They use the same exact hull, but with the turret rings removed and various machine guns installed for protection, so it shouldn't take me too long to do that. Once I'm all done, I can go back to working on historical designs.