Do you, as a GM, really want to mess with your players' heads?

Don't give them everything they could possibly want. Give them more than they could possibly have imagined you'd ever give them.

Do they want riches? Give them a vast business empire. Do your players want power? Give them control of a large country. Do they want bigger weapons? Give them an entire nuclear arsenal. Do they want magic? Give them the ability to create and destroy entire planes of existence in the blink of an eye.

Some players will be appropriately staggered, which is great. Some will, however, simply accept it and immediately see what they can think of to abuse it. So make it come with lots of strings attached. Lots of complications. Lots of unforeseen problems. With something this big, it really shouldn't be too hard.

Transcript

Lama Su: Welcome, Master...
Obi-Wan: Obi-Wan Kenobi.
Lama Su: What can I do for you?
Obi-Wan: I'm investigating a poison dart that was used in an assassination attempt on Coruscant.
Lama Su: Oh yes, we make those here. Of course, poison darts don't kill people; assassins kill people.
Obi-Wan: Do you have records of sales?
Lama Su: Our clients require discretion, you understand. But retail weaponry is a minor side venture. The main purpose is to equip your clone army.
Obi-Wan: My... excuse me? For a moment there I thought you said my clone army.
R2-D2: {inset} You get a clone army?!
Lama Su: I refer to the large order from the Jedi Council, of course.
Obi-Wan: From... the Jedi Council? Uh, yes... of course.
R2-D2: Hey, can I put in an order?