Here's what I told somebody else about it via PM, might as well post it here.
What I did was measure the opening after removing the grill, then my brother, who works as a welder got me a piece of aluminum and a piece of steel both cut to the size I needed to fill the opening.
I used the aluminum because it was WAY lighter than the steel.
Then what I did was drill the holes for the screws to hold it on the head, same as the original grill.
The rack unit DOES need to be offset to the left side of the head or it will not fit. That's the only thing to be careful of really.
Then I just held up a 1U rack unit to the aluminum and marked where the left side of the unit would be mounted and measured over the width of the 1U unit and made another mark. I then cut out the 1U rack space with a scroll saw, since that was all I had to work with really.
I then used a drill/tap to put the screw holes in place to hold the rack unit.
Pretty easy, but just make sure you keep the unit as far to the left as possible when looking at the front of the head.
