Though meant for a spare tire, my GARB (Garbage And Recycle Bag) attaches and removes quite easily at four connection points and can be used independently and stowed inside a vehicle. I do exactly that, in fact; put it inside my trailer at night when in bear country, with a good sealable trash bag inside it, so it is not outside all night attracting critters.
It is made by OLB member
@Virgil of
North Bound Expeditions up in New Brunswick, and I have to say it's an impressive bag.
NB Expeditions is a veteran owned company and both
@Virgil and his partner Nick are good guys to deal with. They have a bunch of other
cool gear too, like a headrest/roll bar fire extinguisher mount, overhead storage system for inside your vehicle, wrap straps, and a chainsaw bag, etc.
Very well made, comes in four or five colors, has lots of zippered and velcroed pockets and a removable divider down the middle of the inside, so you can keep garbage in one side and recyclables in the other. Also has mesh pocket on the right side, a deep tall pocket on the left side, and straps inside the top for keeping a small load of firewood up and out of the way, but under the cover.
It's made of "high-quality CORDURA nylon and PVC lined fabric held together with UV and ROT treated thread" and if you use a product like 303 UV Protectant Spray every few months in use, will stay fade-resistant. Comes in two sizes, the one shown below and a Narrow. Great price, too, especially with the current exchange rate. The large, which is around 22" across the back, is currently around $97 USD, which is what I paid.
Here's an image of mine installed on my trailer's spare tire:
View attachment 56640
View attachment 56641
Besides the two sizes North Bound Expeditions make and the large one
@Kevin108 posted above, Blue Ridge Overland Gear also makes a smaller one that may suit your needs better than either of the larger ones. It too can be used independently inside a vehicle. I have one and am going to use it more for the van now and shorter, non-trailer excursions. I might even attach it inside one of my rear doors. Here's the one I've used with great success:
View attachment 56646
If you come up with a different solution,
@escape_the_paradigm, let us know what you found, so others can do the same thing if it fits their needs.
Road
.