I have the same question, Sgtcomp. Seems like steel plate would help hold heat.
I've had my Chargriller for a few years now and love it. Until joining the Brethren, it never occured to me to make modifications. Mine is about worn out now but I will definately buy another and make some mods to it.
Swibirun shows some mods he made on the 'Brinkman Smoker' thread. Might get some ideas there.
Would like to hear what you decide on doing.