Thank for the comments. Someone…somewhere...did a 4E Mass Effect game using Amethyst as a baseline, but that was back in 2010 and I don't know if the designer ever finished it. It would be a good fit in my opinion. However, the issue is incorporating an adequate system for biotics and honestly, I wouldn't use anyone's magic system for it. I'd create my own.
And yes, I have been thinking about this…and yes it was on my short list of projects before I got sidelined with writing this cyberpunk game for Pathfinder. When that's done, I may do a small supplement for 4th Edition using UM4 architecture to include superpowers. The inspiration for this was the film PUSH which came out a few years ago, though the new TV show Alphas would also fall into that category.
The mechanics I plan would involve using the ladder system introduced in UM4. So as players progress, you can choose class powers or supernatural powers while still benefitting from the supernatural powers granted by the ladder. I also plan on creating different levels of each one, so a GM can declare the scale of the supernatural in his game. So a Biotic would be a Mark 1 or Mark 2 Kinetic, and there would be a Mark 3 as well…at least that's the plan. The supplement would just be ladders and thus not be large or terribly expensive. When I can put this out I can't really say, so I won't be bothered if you take that idea and roll with it before I get my official book out…
As for Amethyst, we use the base wizard and nothing else for the spellcaster. Cleric's require a lifepath. I suppose you could use wizard powers in a pinch. I guess that would work.
Dealing with the breakdown of books, Amethyst Foundations is the core 4E book written before anything else had come out from WOTC. Amethyst Evolution came out later, which included advanced rules as well as classes built for 4E Essentials. We took all our unique rules from Amethyst and expanded them, creating Ultramodern4. Amethyst Renaissance is our Pathfinder edition. If playing 4th Edition, I would recommend both Evolution and Foundations, even if using the larger core classes from Foundations. If making a Mass Effect conversion, I would start with Ultramodern4 (hoping you'll pick up the actually book rather than the OGL) and then add in rules from Amethyst as you need them, as there's more variety in character creation.
We also have a cyberpunk game coming which could also be useful…