After careful measuring, I have ordered a 26" w x 19" h x 22" d, 135 lb (empty) tool box. When populated with my minimum amount of tools, I estimate it will weigh 350-500 lbs. It will fit easily into the second bay, curb side, from the front.
Next step will be sliding cargo/platform tray and will be good.
I just had an interesting though, anyone know the weight carrying capacity of our storage bays? Duhhhhh