Carol, knowing what breed of dog you have might help elicit the most appropriate suggestions. I don't believe you said you didn't walk your dog. It's perfectly normal for people to want to have their dog outside with them without being able to run away into danger, and to be able to 'use the facilities' without a person having to go outside with them. Barrels do not taper toward the bottom, so would provide solid fence sections with no gap at the bottom like the shape of a traditional flower pot. There are individual pots that do not taper, and rectangular planters that could be purchased, or you might enjoy making some, IDK. I would probably use evergreen shrubs, like Gardenia, Osmanthus, Azalea, Rosemary, with other plants tucked between. Knowing how much light this area should get, and what time of day, and your garden zone, would help with more specific suggestions. You can find your zone by typing your ZIP code in the box on this page. Stored in your profile (link to edit here) it will show up next to your name automatically when you post.

You probably don't have any answers yet because you haven't said where you are or how far you would travel. For example, I've got some extra utility pots. Are you up for driving to Seattle to pick them up?

Putting rocks on top of landscape cloth won't cause a perched water table in your raised bed. Landscape cloth is meant to be water-permeable, so the water will go through the bed soil, down through the rocks, and right on down through the landscape cloth. And since rocks want to rise and landscape fabric degrade over time, all you will end up with is a raised bed full of rocks and possibly fabric scraps. IF you want to try making a raised bed into a container, you would need to line it with something impermeable like a pool liner, punch some holes in it so it has drainage but is not permeable, then fill from there. And still, no rocks in the raised bed, because even lined in this fashion the rocks aren't going to stay put and will start rising up. What are you planning on growing that you think you would want to have a perched water table in a raised bed sized area?

Like porknham, I usually use a mason style jar (the small size). Our favourite jam comes in them, so we always have loads of them floating around. They hold enough dressing for two or three large salads and have measurement marks on the side (and never, ever leak). I used to use this Tupperware shaker but it takes up more real estate in the fridge and I prefer a glass container. I still use it for Caesar dressing and popover batter, but it doesn't get the use it once did.