Its been mentioned on here that it is possible to do new story missions. If you were wanting the trigger to be once only then i guess its possible. I haven`t heard of any mods which done this to a high level (though i could be wrong).
It is possible to use commodities, and have a commodity sold at a single base which has a high trade in at its destination. If you add the commodity to the local pirates high scanning list they might attract some attention. But, chances are that the player would just fly to the destination with little or no trouble unless they were already hostile to the factions.
You could also do long range destroy missions of any range, with the commodity set to the loadout of a base or defence. The downside is that the missions are always available, so you could do them over and over again. And they have to be done from the commodity trader, so you don`t get the fluff that you get with most missions. You could do missions like "A fugitive (or local pirate), seeks passage on a fast transport out of Liberty, Bretonia, Rhineland space.. Deliver him to Yanagi Depot in the Sigma 13 system. If he is delivered on time you will be well rewarded for your efforts.."
Then, the commodity is given Decay per second value in select_equip.ini where after a time the contract or commodity dissappears. The commodity itself would need quite a high volume if the value is going to be high. Otherwise players would just buy themselves a large freighter and load up.
So, its kinda do`able, not quite what you wanted but its most likely the nearest thing to it.

cool to hear. I was thinking as some of the people in the bar give destroy missions and give info that can be "loaded onto your nural-net" it might be possible to recieve a cargo or passenger to transport to another bace or even ship. the high payouts would be for missions that leve the system your currently in.

Blessed Be to all those that still dream of the flight to the stars.

Well, It might be possible to do it this way:

(not too sure how missions work, so if I head off in a tangent to reality, don't mind me)
You'll notice in the Manhattan comodities trader there're two extra characters, a cryer rep, and a synth foods rep. Now... if you set up one of these to be, say, a Junker, and gave him a mission that went something along the lines of what's been said before (My boss, X, needs a quick ride to Y. Get him there fast, and it will be well worth your effort), and then have acceptance auto-load the item into your ship. Set up mission waypoints with the fastest way there, and Bam! you got yourself a "We need a fast ship to get this boy and these two droids off this planet" mission.

The same could be done in bars, of course...

Also, there should be different kinds of rewards instead of just money, they should give you like a prototype weapon, shield, or something like that. What about that idea? And also, what about like hiring wingmen? That way, you could pay them to just be there, and in some cases, DIE for you. Of course, when they die, you would give like a thousand credits to his family. What about that idea?

I used to be The_Corsair, now i am Unsung_Hero. Sorry for the headaches that I cause.

There`s some nice ideas, but I still can`t see how it would be added to the game. The commodity missions work, adding things like wingmen would be good, but its been mentioned before and its regarded as not possible. The only way to add new missins is to know completely what all the nodes do in vinigrette params nad they`re not very friendly.
Story missions have been mentioned by a few people, I`d love to be able to create story missions which are triggered buy doing simple things like talking to a person in a bar or entering some distant base, but its gonna take a long time to learn and i`m already spending more time modding than I ought to.
Someone will work it out i`m sure.

thanks for the info all . I hope that someday either someone will crack the code ( find a way to add storymissions) or I get enough free time to look into it myself (as in "hmmm what happens when I do this? " best of luck to all of you in your various projects

Blessed Be to all those that still dream of the flight to the stars.