You might not be able to find a ready made bag with all of your specific requirements. That said, buying a custom made bag might be your best option. When I was looking for a real bike messenger bag, not a shoulder bag, I spent weeks searching and researching for ready made bags. When I couldn't find one, I then spent months contacting custom bags makers in Canada and the U.S. through email inquiring about custom work with my specific needs and requirements. I did get a handful of replies back but many did not. The ones that did, weren't able to build my bag since my requirements were too specific and wasn't available in their stock options. I found that quite a few 'custom' bag makers offerings were you choosing the size of bag you wanted, picking colors for the flap, interior, exterior, pockets, you might even be able to choose the type of material used for the bag and then whatever stock add-ons they offer to their specifications. While to most people, that level of customization is adequate, it wasn't quite perfect for me. When I did find a bag maker that was willing to alter and modify a basic stock design and include my specific needs, I was set. After almost 30 emails going back and forth with ideas detailing what I wanted, measurements, suggestions and so forth, my bag was finally ready to be built. Although I did pay a premium for the bag, I believe you get what you pay for. In my case, I have exactly what I wanted. An overbuilt bag that will last a lifetime. No disappointments. No regrets.