Hi Warren, I was directed over here from the Q&A board.
I used to use such a feed from Quote.com a few years back. I have my own model that stacks various stocks up against each other and attempts to take advantage of the asynchronous nature of swings to gain shares of either, or both securities. Strategies are created based on the present prices and monitored on a real time basis for selectable departures of from 10-20%. If Stock A goes up 10% and stock B declines proportionally, the model recommends movement from A to B. After such a trade, reversing strategies are generated and likewise monitored.
The whole thing is in Excel.
Unfortunately, Quote.com went to the dogs, and I've never seen anyone else with the capability. So now, I take a static dump at the end of each day from Fidlity active trader pro and populate my model. It's a klugey process dumping comma delimited asci and is a bit of a pain. The dynamic feed from quote,com was quite elegant.
regards