A 7 cell NiMH flat pack is about 155-160mm long (generally right in the middle, at approx. 157mm), and I have fit those in a Rustler chassis with the back wall dremeled out no problem (still had a few mm to spare too!).
Just throwing that out there as an option.
Last edited by Five-oh-joe; 05.19.2008 at 12:35 PM.