A suggestion? You could try to move your brake servo further forward and make a new brake linkage. This would give you more room on that side for longer batteries, like Lipos. Even if they are on one side, the balance should still be very close since Lipos are lighter and you have the motor and some of the tranny on the other side. You could mount the receiver and ESC on the same side of the motor and you should be golden. Just my $0.02.
Thanks for the tips and suggestions, I appreciate your input. Still a work in progress. Sounds like a very knowledgeble group here, so I am sure I will be updating this thread with many more questions.