Different brand lipos have different sizes. I am running a TP 5S 5000 - Dimensions (WxLxH): 42x48x160mm and it is just to big, makes the side of the body sit up abit
Also depends on layout. If you split it into two 2s packs and put them on either side, you can fit higher capacity packs. Of course, this limits motor placement. Also, you can raise the body a bit if running really close.
i can fit 2 4s 5000mah Maxamps on my hyper 7. Granted i dont do this but they will fit. BTW this is a perfect fit. Doent push the body up at all but there is no room left for another cell.