Yes, modular tanks have been around for a while. It works but it's not as useful as one would think and, back then, was more annoying than anything. With the UI improvements that Meridian implemented, it would be more useable.
But I think Dioxine has plans to make tanks a soldier type and the different hulls/turrets can then be armors and weapons. If this is the case, it would be unlikely that he would be interested to implement this.