If you want to branch out into different brands then I think the Tyrant, Scandal, and No Rules Exist fit the bill. The original Mastermind was a pretty early and rolly ball, even for a high-end oiler, so if you want a similar shape not all of the new top-end stuff will be close.
The Jackal Ghost and LE might be a bit cleaner and more off the spot than the original Mastermind. That's how most of the high-end solid asymmetrical balls are trending these days. I mean don't get me wrong they will still be a a high-end solid asymmetrical, just not exactly what we were seeing a few years ago.
Of course that's not a bad thing for the most part. Might be a better fit for you too, hard to say that looking at a computer screen though. I think you will be fine with just about any choice among the high-end solid asymmetrical balls from any company. The only one I would not go with for a replacement is the Maverick. Great ball, but really clean and strong off the spot for a solid. Quite a different shape.
