I don't know where you can find it but I have a teeny tiny bathroom too and I love this wallpaper for it!

Nina Campbell makes an amazing wallpaper that is black with birds on it- it is beautiful and great for small spaces. You can buy it at Osbourne & Little.

This wallpaper is beautiful--a return to refinement. I love the slightly "Asian" attitude.

(The pattern is called PERROQUET and it comes in black & lighter colors as well).

Shumacher Chiang Mai Dragon comes in a similar turquoise color and chinoiserie motif, although a bit busier. Shumacher's Birds and Butterflies is similarly themed, although without the vibrant background

Check out this collection, there are some similar patterns:
http://www.degournay.com/wf_chinoiserie.php

You could also consider putting some chinoiserie fabric on the wall, I think there have been some tutorials here on how to do that.

You could paint the walls in a gloss paint matching the aqua (or whatever you prefer). Then use decals, stickers, and/or paint to duplicate the look of the paper. Hiring a faux finish painter might e cheaper than vintage paper.

Not as gorgeous, but here's something similar on ebay.
Perhaps you could use it as a base, adding more colourful details to get the full effect you are after?

http://www.ebay.com/itm/GOLD-BIRDS-ON-ASIAN-BLOSSOMS-ON-GOLD-CRACKLE-ON-GREEN-WALLPAPER-HA1343-/180895410873?pt=LH_DefaultDomain_0&hash=item2a1e34eab9

. . . .and here's a site on Etsy that has a chinoiserie wall decal in your choice of colours that might work if you want to try SherryBinNH's idea.

http://www.etsy.com/listing/88191660/vinyl-tree-wall-decal-wall-sticker-art?ref=sr_gallery_10&ga_search_query=chinoiserie+wall+decal&ga_view_type=gallery&ga_ship_to=ZZ&ga_min=0&ga_max=0&ga_search_type=all

Try Thibaut's Tea House collection - the Cantonese in pearl is stunning:

http://www.thibautdesign.com/collection/old_collection.php?patternID=782&productID=4395&material=Wallpaper&colorID=3

I searched for the same thing for a long time for a closet. I never did find anything quite exactly like I was looking for. But what I did do finally was buy this: http://www.amazon.com/gp/product/B005WYBBDO/ref=oh_details_o05_s00_i00 while it's not exactly the original aesthetic I am happy with the results.

I also looked for just fabric which would look like that, and I wasn't able to find anything, but if you can you can always apply that with starch.

Cole & Son wallpaper (www.cole-and-son.com) is great for English and organic wallpapers, especially "Woods" which is carried by Anthropologie. Though, it's pretty pricey.

If you want to go all out this is an AMAZING company on Ebay. Its all handmade and hand painted silk wallpaper, It costs a fraction of the cost of companies like Fromental. And although pricey is a completely unique wallpaper that they can manufacture to your specific requirements or any colour.

http://www.ebay.co.uk/itm/Chinoiserie-Handpainted-Silk-Wallpaper-Custom-Size-/250676498799?pt=LH_DefaultDomain_0&hash=item3a5d7bd16f

Check out what it looks like here, although she has done it in panels rather than the whole wall.
http://littlegreennotebook.blogspot.co.uk/2012/02/chinese-wallpaper-in-acrylic-frames.html

And if we all won the lottery:
http://www.fromental.co.uk/catalogue/wallpaper/chinoiserie/

I'm sure whatever you choose will look great.

I'm the one who asked the question - THANK YOU all so much for your ideas and suggestions! I have a whole row of new tabs opened, and hopefully I will find something similar. Didn't even know it was called "chinioserie" - that will definitely help me find what I am looking for! Thanks again, and thanks to AT for featuring my question.

Amongst the Chinoiserie Paper firms, I think Griffin and Wong (www.griffinandwong.com) and , perhaps, DeGournay are probably the most approachable regarding customizing details on projects - and might be able to approach that style for you.