I am sure that you have seen my savage build. I used some fd battery trays and mounted them as far forward as possible. My truck jumps well, and does not stand on its rear bumper while it is in the air. In fact I can hit decent sized jumps at 40+ mph and it flies flat and low. I really need to make a vid of it.
Heres a link to my build:
http://www.rc-monster.com/forum/showthread.php?t=11140 Pics start on page two. I can say that I am very happy with everything I have done, and would not change anything.