I notice when looking for ways to carry things on my bike the diamond frame has a great number of bags and accessories made to fie in the opening formed by the diamond shape. Hanging a bag from the top tube for example and I also notice begs that fit the V in the front. I like this concept as it gives another large space for stowing gear. I was also thinking of designing a bag that could hang from the cross bar to store an extra 36v battery pack. I don't think anyone makes one commercially but shouldn't be to hard to make utilizing velcro straps and some sewing. Just need to find a bag large enough and the rough shape to start. I know I cold put one in the rear rack bags but want them for other items. Anyone tried this or similar way to carry an extra pack?