The Aeon games (Adventure!, Aberrant and Trinity) will be released by Sword & Sorcery Studios as separate hardback books. They will be d20 books based on 3.5 (not d20 Modern, not M&M) and using their own proprietary systems for psionics, superpowers, etc.
I don't think any of these books would be particularly helpful in a Mage conversion, because none of the powers in the Storyteller versions of these games (Psionics in Trinity, quantum superpowers in Aberrant, or pulp Knacks in Adventure!) work like Sphere Magic in Mage. If you really want a d20 magic system that resembles Mage, your best bet would probably be to use the Ars Magica system as a "Rosetta stone," look at the mechanical similarity between AM and d20 and the conceptual similarity between AM and Mage, and work from there.
It actually wouldn't be hard to do a mechanical conversion, just make Arete a level-based ability of the Mage class similar to BAB and have the characters purchase sphere levels as feats. You could have a subtly different class for each of the Traditions and Conventions, providing appropriate class abilities. It would be a lot like Jedi in SWRPG. Sphere Magic is actually not that mechanically complex (it's conceptually complex, but that's a different kettle of fish). The real issue would be that Mages would be grossly, grossly overpowered relative to any other d20 class or race, and would therefore offend the Balance Police.
KoOS