As far as I know this is how the brand would attack you, if they wanted to: they would have to demonstrate that the Millennium Falcon is a "copyrightable character"; secondly they would have to demonstrate that you have indeed produced a representation of the Millennium Falcon.
A related reference is the Batmobile lawsuit, see here and here.
You are in a gray area.
In the above case you admit yourself that it's a tribute to the Falcon. But on the other hand I didn't quite recognize it at first sight. So it looks like if you avoided referring the Falcon in the first place, you'd be more likely to be in the clear.
Secondly it's okay in the US to create representations of utilitarian things (such as branded rice cookers, cars and buildings) (discussed in above links). But the problem here is that arguably the Falcon is not utilitarian, it's just a work of art. If a judge ruled the bat mobile a copyrightable character, I can't see how the Falcon wouldn't win that too.
Be aware that these laws vary by country. In Japan you might see representations of utilitarian things but they always mangle brand names, for a reason: the law is even more unclear as to how this (like, drawing a character holding a Sony walkman) should play out in court.
Finally I think you should read on Blendswap about how they handle "fan art". The bottom line is that the industry isn't attacking fan art nowadays (they could, but it's mostly detrimental to them), at least not until it makes its way in other commercial products. As such it would be okay for you to upload your model. But if you (or somebody) refer to it as Millennium Falcon it would get labelled fan art and this is a big deterrent to devs for using it, let alone in a commercial game.
Since I wrote that much, I might as well let you know that I'd be happier to see you producing original stuff.