I was going to say it's not that big, but currently it 87" tall, 88" wide, and about 77" deep, so that's pretty big... Actually that's good to know as I think I'll have to mount my Z servo off to the side of the Z ballscrew instead of above it. And to answer your question, the Z ballscrew is in the 'normal' place on the z axis. It's in the images above, but it's tough to see due to the resolution.
I did some more fea over the weekend, and a lot of the deflection in the x/y table is coming from the 0.25" wall tubing. The walls are flexing a lot near the bearings but not in other places. This is leading to about as much deflection of the table as the spindle is seeing. So now I'm switching over to a more solid platform for mounting the x and y rails. We'll see how that goes...