Five gallon buckets work great Jeff. I don't worry about them being trashy as I just about always clean up a few things dumped where I park. I sure pack out more than I pack in.
I make blinds out of everything from split burlap bags to carpet scraps and they work. The added benny of a GB is they keep the wind off you a bit and feel 10 degrees warmer than being up the tree..
You can also stretch your legs out when you want without the movement being an issue.
I think I remember you saying you always carry in your climber. It will be a pleasant change to walk right in and sit down...