http://fiatleak.com/
This tool supposedly gets data from "Mt. Gox, Bitstamp and BTC China to show you which countries and which currencies are moving in and out of bitcoin in real time." I'm assuming it's just Mt. Gox and Bitstamp now and possibly others.
-http://www.zerohedge.com/news/2013-11-11/meet-fiatleakcom-%E2%80%93-real-time-map-bitcoin-transactions-country
UPDATE
As of September 2019, the exchanges from which the data seem to come are listed under "exchange" in the bottom left of the tool. Perhaps take it with a grain of salt, as there's some obvious errors, such as gdax still being listed along with coinbase pro. Gdax was rebranded as coinbase pro about two years ago. The listed exchanges are:
- bitfinex
- bitflyer
- bitmex
- bitstamp
- bittrex
- cex.io
- coinbase pro
- exmo
- gdax
- gemini
- itbit
- kraken
- livecoin
- neraex
- quoine
- yobit