I wouldn't be worried about head room, I can head butt my console from the drivers seat if I lean right and I can use it as a leaning point on long drives but the chances of someone hitting it if it went into the back seat under normal conditions is low.
Apart from something so big being impracticable for me I'd be worried about the weight of it, mounting points aren't really plentiful and you'd have to pull the roof skin to see just what is up there. Despite going past the B Pillar most after market consoles still mount to the B pillar which I can only assume is because the other ribs in the roof channel aren't strong enough. When considering strength you'd have to take into account bouncing weight not dead weight.
From what I was told (and it's not definitive) lack off support is why we can't have shelves like F Series utes have, visibility is also part of it but there is not enough easy points to mount to that takes the bouncing weight of map books, and shit people stack up there.