Solar Backpacks as Trunk bag
 

So I was looking into those solar chargers that have been discussed recently and thought that I could kill two birds with one stone using one of these backpacks as a trunk bag. Anyone ever use one of these or look into it?

These are the bags I've been looking at.

http://www.voltaicsystems.com/

http://www.earthtechproducts.com/p4.html
http://www.rewarestore.com/jb_es.html

The Juice bag looks like it charges a little faster.

Too bad no companies like Arkel or topeak make bike specific trunk bags with solar panels built into them.

I wonder how durable these bags are.