It seems like a lot of work and expense just to move the bottle back to the rear. If your concern is the size of the bottle, I think a pint recovery bottle is all that is required. That should free up some room. Plus having it under the hood makes it more convenient to check after making a pass. You might tend to ignore it if it's out of site.
Ours is mounted on the passenger side of the radiator with a petcock on the bottom.
