good work! i would put some wider cross bracings between the two pods, bend your flanges inwards and fiddle with your cheese holes a little. your lacking in some of the major stress areas and triangle departments. concept has some serious potential though. also if you run your cross braces to the outer plate of the drive pods they do a lot more for you.
take a good hard look at the slideshow in this :
http://www.youtube.com/watch?v=_hTyXQUgYLE at how thier chassis is put together, pm or IM me if you wants some help with this.