There is a Sponsor Power on the list already, for what it's worth. It's not very nicely formatted though.
I think Unlimited Blade Works needs something extra. Any ideas? I'm not familiar with the source material, so I don't know what's appropriate.
As for Reality Marble, how about this:
REALITY MARBLE [-1]
Description: You can travel to a magical sub-universe of your own creation and drag other people with you.
Skills affected: Conviction, others.
Effects:
Reality Marble. As an action, you may spend a Fate Point to enter your Reality Marble. If you wish to bring other people with you, you may roll your Conviction skill. Then every other character within a zone is forced to enter your Reality Marble with you unless they beat your roll with a defense roll using Conviction or Athletics. People drawn into the Marble remain there until you decide to send everyone back or get knocked unconscious. However, you can't keep people longer than the time indicated by adding your Conviction roll to "half a minute" on the time chart.
Different Rules [-varies]. The laws of physics are somehow different in your Marble. Negotiate the effects and costs of this upgrade with your GM. Examples to come.
That looks pretty good. As for other things with Unlimited Blade Works I don't know, I'm about to watch the Unlimited Blade Works movie in a couple days so I may have something then. Maybe with Unlimited Blade Works it gets a duration boost automatically? That would fit in line with the power, it's meant to be fired for extended durations in rapid fire.
As for reality marble itself, that looks like a good write up. It's also an ability that is supposed to be different for each person using it. So it might cost differently based on the abilities it goes with in it, which I think is what you have in different rules and would work perfectly.
One other reality marble I remember off the top of my head,(wasn't technically an RM I think but it more or less is one) is a giant Roman theater where the user's attacks bypass all armor. So I guess it'd be a -4 cost in line with Mystic Eyes of Death Perception for that one.
Would Reality Marble be adujudicated similarly to Reality Warper, but only while you're inside the marble? I could see it as just Reality Warper or Demesne with a bunch of upgrades, and a Cassandra's Tears-esque ability to place world aspects, like THE NAZIS WON, DINOSAURS EVERYWHERE, or OLD WORLD OF DARKNESS.
I'm not familiar with reality warper but yeah, it's only in effect while inside the Reality Marble. They are really fun 'worlds'. They tend to look more like a giant stage than actual planets or such, good for dramatic fights.
The Unlimited Blade Works reality marble is just a barren wasteland with and endless amount of swords stabbed into the ground in crooked angles, with massive metal gears turning in the sky. Here's the two picture examples of UBW and the other one I mentioned a second ago.
Unlimited Blade Works:
http://images1.wikia.nocookie.net/__cb20120508175621/typemoon/images/b/bf/UBW.jpgAestus Domus Aurea:
http://images4.wikia.nocookie.net/__cb20110325200829/typemoon/images/thumb/e/e9/Aestus.jpg/1000px-Aestus.jpgThe way they tend to work, is like a Demesne except they have one specific thing they do normally. So the World Aspects would have to be set up ahead of time when you first take the ability. Though you could possibly change the Reality marble later, it would have to be a certain amount of sessions later and maybe after one of your aspects had changed. The marbles are supposed to be physical constructs of your inner self or something. I am speaking fairly loosely on them but I believe it's correct.
So someone's reality marble might be a case of them having ton of speed, toughness, and recovery, and flight abilities in in a world without light.