Hi David,
I'm not sure why Don opted to do it this way, but I'm sure he has his reasons. I believe in the end he had to split the remaining space between the header pipes and your foot and only wanted to make just enough room for the pedal assembly. I would assume there was no point in moving the box deeper on the passenger side because there is plenty of space. You can't put electronics in there, although I love your idea, because it would be hard to get to them and they may be affected by heat. Don is out for a few days, but I'll have him comment when he gets back.
Thanks,
--Mike / Turn Ten Racing, Inc.