I've purchased a few feeders from Canyon Trading Company of Gilbert, Arizona, for my own use and have given them as gifts. The nectar goes into test tubes closed off by a rubber cap with a small hole in it. These then slide into copper spirals that come off a copper wire frame. The frames are hand-made and are available in hanger, window- mount, and hand-feeder versions with differing numbers of perches. The open design of the feeders make it easy to see the birds and it is especially impressive to see their long tongues lap the last drops of nectar from the tube. The small volume of the tubes ensures that the fluid will disappear long before it goes stale. I keep a supply of filled tubes in the refrigerator and swap them frequently. Cleaning test tubes is quite easy - just make sure to soak the cap end in a little warm water for a couple of minutes to dissolve any crystallized sugar prior to taking the cap off.
The company appears to do most of its business through art fairs and a small number of distributors. Since there weren't any of either in my area, I called them and ordered directly. Friendly service from what seems to be a collection of hands-on craftspeople. I have no affiliation with them apart from being happy with my purchases. The gifts have also been well-received. These feeders are just different from anything else that I had seen on the market and that motivated my first purchase.