Quote from j_medved:
http://www.quotetracker.com
can be used with various datafeeds. With IQFeed and eSignal you get all the exchanges you mentioned:
(http://www.quotetracker.com/iqfeed and http://www.quotetracker.com/esignal)
Quote from lynx2004:
Can quotetracker chart..let's say a spread between two prices or a ratio between two prices or some similar formulation, real-time? In other words, a custom indicator of sorts...? thx