What an absolutely brilliant concept, and so neatly executed. If I feel the need to install a booster (split circuit brakes are on the cards) this is how I shall do it. I was trying to come up with a way to do this whilst retaining the original pedals (I don't like pendant pedals, I believe the pivot should be as close as possible to the driver's heel), but failed.
Just a couple of comments, firstly, would it be possible to eliminate the bends in the pull rod? These would tend to straighten out under tension leading to lost motion and a "spongy" feel to the pedal. Was this detectable in practice, I wonder? One way would be to put the cross shaft through the chassis leg level with the pedal shaft, but further forward, just ahead of the suspension eye bolt and have a straight pull rod passing below the bolt. The actuating lever for the master cylinder could then pass up through a slot in chassis leg capping plate. The mounting bracket for the master cylinder/booster could then be welded direct to the chassis. The whole lot would be more rigid and the fabrication simpler. Can anyone think of any snags? The downside, of course, would be more bodywork mods. Nothing that couldn't be reversed if one wanted to revert back to standard, of course.
Unfortunately, I won't be able to try any of this anytime soon, as I have several months, if not a year or two, of bodywork repairs ahead of me, but will keep you posted if I do go ahead.