What is the origin of the expression "I wouldn't ... for all the tea in China"? I've heard it from a British speaker, and I am guessing it may be of British origin, but I couldn't find a reference for it.
The Facts on File Dictionary of Cliché by Christine Ammer says:
not for all the tea in China Not at any price. Eminent lexicographers [such as Eric Partridge] agree that this term originated in Australia in the 1890s and soon spread to the rest of the tea-drinking English-speaking world. The OED cites K. Tennant's Ride on, Stranger (1943): "I'm not going to stand in my girl's light for all the tea in China."
The earliest result for "all the tea in China" in Google Books is in 1895's The Amateur Fisherman's Guide by Charles Thackeray. There's no preview so it cannot be verified, but it's plausible as Thackeray also founded the Amateur Fishermen's Association of New South Wales in 1895.
The earliest result The Phrase Finder can find to verify the date is from an Australian 1914, but I found an earlier instance in New Zealand's Marlborough Express of 9 September 1907 (actually in a "What The Papers Say" section, credited to the Post):
A short time ago the Celestial maiden would not exchange one of her tiny, disfigured feet for all the tea in China; if she lives long enough she will probably weep salt tears of regret that she is not in the fashion, and, even though respect for one's elders is commoner in China than it is in, say, New Zealand, may in her heart feel bitterness against her parents for not having been up-to-date.