Have you looked at farrow and ball wallpaper?

It may be out of print....but possibly some supplier or dealer has some left. Doesn't look like you would need a lot. But I don't know how to go about finding a dealer with some back stock...
But since you have a sample....could you find someone to make a stencil? or do it your self? Add a few brush strokes to the stencil and you've got not only the painted look...but actual paint!

Take a look at Cole and Son wallpaper. Maybe the Egerton pattern might be a possibility? Their papers do look hand-painted.

I would consider stenciling. It satisfies the variables that you want it probably isn't any costlier to have done, plus when you want to chg it, you don't have to strip it. You just prime and paint over it! .

Thanks so much everyone! Deleteduser and Daisychain01, I do like the Cole and Son Edgerton wallpapers, and have an appointment to look at some Farrow and Ball, so thank you for those tips!

ksissy and Lindac92, I had never even considered the possibility of stenciling, mainly because I don't think of myself as a creative person I guess, but your suggestions make perfect sense - especially considering the subtle and simple design that I like. I do have a friend who's an artist, painter, so I'm going to contact her and see if she can help me to create something easy to do that gives me the depth that appears in the wallpaper with the different gradients of the teal coloring. The more I think about doing that, I realize the more special the wall would be! It isn't that big of an area, but is sort of the focal point at the end of the kitchen so it might be really exciting to try something like that. And, thinking about creating my own work (I probably simply trace the stencil from the wallpaper that I have the sample love) opens up my mind to some different colors. I'm going to look around at provencal designs to see what else I might like as well as the teal.

Thanks everyone :-)

Have you tried browsing wallpaperdirect.com

Lots of British designs and brands

Gorgeous Wallpaper Designs

Please show us the finished product after you decide.