If you have the 600iE, you have the origin rover already.
Ground vehicles are reaching saturation I think. Unless there is a viable reason for that type of gameplay, I think ground vehicles will play only a small part in the grand scheme of things.
Back when they had restricted landing zones, ground vehicles made sense. I need to land at a platform X km away from my target. If I don't want to spend hours getting there, I need a ground vehicle to get from the landing pad to the place of interest.
Now, I can just fly up and land next to the place of interest. In fact, it's probably better if I do, because I will have a ship with much bigger weapons on it, so I can take out those turrets much faster and from a distance further away. Even if I am facing massive air defenses, it would make sense that that same place would also have massive ground assault defenses as well.
It's definitely getting to the point of diminishing returns for vehicles. Party boats, fighters, capital ships, large and small mining, fueling, salvage and repair ships. Exploration and cargo ships of all shapes and sizes, etc. How many more ships do we need?
I'm getting to the point where I no longer care about ship sales because there is nothing really "new", just a rehash of stuff already out there. There are a few ships I am interested in that I might get when they come around again, but it will all depend on how things go and what they come up with.