I have a Loring pack basket attached to an old external back pack frame.
It's probably overkill for what I do, but I've had back issues for years. Carrying a bag pulls me to one side and causes issues for me pretty quickly.
What size (height) is that pack basket? I was thinking about doing this with one of the fiber tuff packs or just a kitchen size garbage can. But I like your setup way better.
I think it's about 14"-15" across and 11" front to back, and 26" or 28" tall Roughly anyway, I don't recall exactly.
Loring makes a few different heights, I don't know if they all have the same footprint.
That load sling I bought on eBay from a guy who makes them. I thought I would use it for meat or hauling a small outboard, but I still haven't. The basket could be attached without it. Just use web strap, rope or cord.
I've used a couple kitchen cans in the past, but broke them. But they are way cheaper and lasted a fair amount of time though.
I do use it occasionally for hauling stuff other than trapping too. But the older I get the more excuses I find for strapping less and less junk to my back.
Edit: I just realized the load sling panel wasn't real visible in the original photo. Added another one I had