Does anyone know a maximum poly count in which Unity will start choking up at? My game will have about 60 - 100M poly at one time so I want to know, if Unity can handle it…
Unity can, I doubt your hardware can, though.
You’re probably going to run out of memory for your system by the time you hit 50 million. That assumes that your hardware will even let you load the objects, of course.
I’ll give you a hint at just how many polys 60 − 100 mil is for a game engine to render. You remember Crysis (you know, the game that no one could really run at the highest settings)? Well that game, at the highest settings, never let you see more than 3 mill+ polys. 3 million.
Unless of course you mean loading an entire level with 60 − 100 mill polys and only showing a few mill at any given time, in which case, yes it should be doable.
Yes, I didn’t mean that 100M polys will be on the screen at once. Meant whole level. 
Thanks
I think it should be able to handle it. I know if it can’t it would have some sort of warning. 
I think you need to optimize your meshes significantly, and use techniques like bump maps, displacement maps etc, to suggest the high detail for the meshes. This reduces the tri’s/poly’s of each by tenfold at least (if doing correctly). Visually it’s barely visible, but for the renderer and hardware it’s much easier.