That does look very neat!
But if you fancied doing it for about £10-15 you could by a fuse box with enough fuses in, an a relay and a relay holder?
Put it under the rear seat or luggage area, have power from the battery to the relay then to the fuse box, and have the relay switched by what ever you want, be that igition or a switch?
That kit does look like a relay fuse box to me, and does look very neat.
Sounds a lot of work, but I managed it, and So that means anyone can!!!