Well some times the best ideas are the best, often the case in the world of product design and those supports will help with reducing flex. As for the servo mount it should work but I recon if you hit a rock in the right place it will break, I would recommend finding something that sits more flush with the chassis like a plate of 2mm thick aluminium with counter sunk holes and give the edges a slight chamfer (sloped edge). But if you have good ground clearance and there aren't too many bumps on the surface you are running on it should work great as it is, keep it up .
And the job lot of RC sounds good, that should keep you busy
Alex Simplest ideas even :L