OK, I took a photo of some gear on top of an outline of the battery pack dimensions. The inside of the pack will be 300 mm by 200 mm, with about 10 mm of acetal plastic all around (not exactly, as the sides will be 6 mm and the front and back will be 8 mm, but I have estimated about 10 mm either side for simplicity).
The switch gear will sit on top of an 8 mm false floor, and below this is the LiPo pack. The maximum height is about 60 mm, over which another final cover will sit.
Please excuse the MS Paint mock-up, but I have drawn in a pack-splitting contactor, as well as the main output contactor, a shunt, two fuses for each half pack, and a control box which will contain the high voltage DPDT relay, power on delay and so forth.
As you can see, you run out of room pretty quickly. Two 352 V packs is surely safer than one 705 V pack, so taking charge leads from either side of the contactor and pairing these with the main pack terminals will give two floating packs which are fused.
There will also be physical separation of the fuses and contactor at the back from the shunt and contactor at the front via a small wall as high as the walls, so it also gives a bit of strength should the bike to a tumble.
All look reasonable so far?