I found a cell that fits perfectly into an E maxx battery compartment.
3200 mah 15c. $14.50 a cell (does not include shipping from hong kong)

Ok measurements of my IB 6 cell pack 7.2v 5 1/4" long, 1" thick, 1 3/4" wide.

These cells are (rough conversions) 5 1/4" long 135mm, 1 3/8" wide 35mm, 1/4" think 7.5 mm.

So a 3200 mah 2s would be 7.4 v and 1/2" think $$$29$$$ plus shipping
a 6400 mah would be 1" thick 2s2p $$$58$$$ plus shipping.

We need to get together and order a bunch of these to get a better rate and cheaper shipping. I used to import lipos for planes. Did this for a few years so I know how it works.(My major retailer was www.3dfoamy he still has a few if you want to check out my story Great Things batteries)

Who's in with me. I am not in this for money but to get some batteries for a little cheaper.

Or get RC-Monster to get a bunch of these.

Dan