Here is a camera bag insert that my mom made for me for Christmas and I LOVE it!
When I bought my camera I got free camera bag, which in my case means a basic and boring bag that kinda works. I believe my mom found some examples on either Etsy or Pinterest and designed this one just for me. I fits perfectly in my purse - the Miche Big Bag - so it will work great when I want to bring my camera along with me.
She made lots of pockets both on the inside and outside of the insert and she made the padding inserts inside of the insert adjustable by using velcro so it will fit any lens. This insert also just so happens to fit inside of my basic & boring camera bag that I already had. I took part of that bag and recovered it with matching fabric that my mom gave me so that I would have a top for my insert (see bottom right picture).
My mom said she had some pointers on making a camera bag insert so if you are interested just let me know - I can see if she would want to pass along some of that information.