I've been looking at a recent bundle which has cool simulator games, and I was just thinking how awesome it would be if games like these had some role-playing aspect, or a plot even. Games like Freespace and Star Wolves come to mind, but they're not entirely it. I mean, I really like the idea of a Ship Simulator Extremes type game with some sort plot or rpg gameplay; FPP rpg gameplay would be easier to implement, I suppose.

bundle in question: http://www.bundlestars.com/all-bundles/extreme-sims-bundle/

King of Dragon Pass is the first thing to come to mind.

edit: eh probably not what tc's thinking of though

So basically a sandbox game?

I'm still waiting for that holy grail of space sandbox games - the game that allows you to seamlessly land on planets, enter your ship, walk around it, walk out of it, walk around cities, trade and interact with NPCs and explore a procedurally generated universe. Alas, there have been space sandboxes that do one or some of these things, but none that do all of them.

Euro Truck Simulator 2 :)

My head just exploded trying to fathom a genuine combo of the two.

Euro Truck Simulator 2 has a level-up system. It's a genuinely good game, too, which is nice.