Stackable portable chargers range with accessories.
Make a uniform width/depth portable charger size, and a thin one = 5000mah, a thicker one = 10000mah. You can click them ontop of each other and aggregate their power.
Each comes with say 1 USB out+in.
When you stack these in+out aggregate so they can parallel input charge to any of the batteries needing to recharge, and all ports are producing power. Say then you stacked the 5000+10000 you'd have made 15000mah with dual input dual output. If someone wanted a much faster recharge they could buy more of the smaller, or if wanted it lower cost in total buy fewer of the larger.
Then, you can overcome the 26800mah (100Wh) limit of TSA as you can unstack them to the higher limit and stack them together to make one huge >26800
You could then accessorize the stackables, you can have a thin one which just made light, or one you can put in the middle with a SD slot of SSD. You could have a stackable with unfolded into a larger solar panel (made of 4 panels the size of the width/depth of one stack).
For the width/depth, consider the Powercore 5000 slim as the sort of size of the stack I'm thinking, a thicker one = 10000mah then you stack away. That size would make a decent top surface for the unfolding solar panel and you plug in a smaller or larger stackable portable charger to get to the weight/cost you seek.
You can then standardize on this stackable platform and then as individual layers in a stack age/fail they are replaced but without having the huge recycling problem of Anker's current one-sealed-unit concept.
You can make future stackable layers with different ports in/out so that someone can add a type of port without a full portable charger replacement, and you pick'n'mix them to get the quantity of each type. e.g. a Firewire stack so you could then say have Firewire on one stack and use, say, a USB-C output on another stack.