So one of my biggest complaints of the BrickPi is it is massive, trying to fit that massive smart brick in and in addition mounting a battery pack not compatible to Lego’s to a mobile robot is well… Hard.
Sorry about the prepositions. 
Anyways what if we could combine the batter in with the BrickPi and make it thinner than the current BrickPi! So I can see @shoban @cleoqc and @JohnC scratching there heads on how its possible. However the solution is quite simple. If the Raspberry pi3 compute module was built into the BrickPi there would be enough room for the battery pack, if modified to fit where the Raspberry pi is. Also if lithium batteries were used the BrickPi would be thinner. Now the price would go up quite a bit, but if offered as a separate model, well maybe someone will buy it. Maybe. It was just an idea. Since Brickpi is open source someone could build this…