I think we should draw the line of what is possible, and what is not;
Stressing the server with realtime calculated values in every base, and crosscalculating to the other bases that sell/buy the same commodity within uncircular waves will absolutely drive the ping, the lagg, the latency and every single network packet nuts. Apart from that, I can only repeat what I said above; the economy must never, ever be solely player driven. So I'm more with Fletchers approach. Slow and steady wins the race.
I could think of the following approach that could meet all ends;
Game logs are determining which commodities have been bought and sold while the server was up for the day. At shutdown, a database takes over and analyzes the data, giving the amount of which commodity prices should slightly change from the bought / sold stuff at which systems. I take only the stations were actually there was something bought/sold and not the other ones. Think of it as; "The grocery doesn't have the meat I want... so I visit the next one."
Database checks for altered commodity prices and how much units have been moved from that; if a route that has been edited was not used to that extend, autorebalancing takes place.
Still, I really would like to see a maximum storage capacity for commodities. The base in the example that buys copper does not have infinite storage capabilities and will say sooner or later "We're full... we cannot take what you have to offer". The same as any production facility will say sooner or later "we have no units left to sell, please come back later". Though I do not have any idea if that is actually possible.
The bar News that changes when the prices change (or rather, it reflects the actual prices when the visitor looks at the news) is a very cool idea, and is in possible in simplified mode (see my listed example). It would be just another file to automatically update when the server is shut down.
Though I have no idea if it is possible to alter the scrolled text, as it is based off the station prices you are currently docked at. I'd rather make a fixed text News Item with the title "Current System commodity price changes".
To hunt the prey is life,
to lose the prey is death,
to hunt the loss is insane...
