I actually have made a nice project with emachineshop :)
I have not updated lately my rcpics, but last year I have used custom fiberglass battery tray for 4S Maxamps 10 Ah.
http://www.rcpics.net/view_single.php?medid=86122
> HB L2PE + MMM + Medusa 60-1600 @ 6S A123
> HB LSP + MMM + Medusa 70-1600 @ 6S2P A123
> AE B44 + MM + Medusa 50-3300 @ 4S A123
> AE J82 + SW 5700 @ 2S LiPo
> AE TC5R + MM 6900 @ 2S LiPo