I'm trying to point out that Mongoose (or us fans) can always build custom universes for ACTA games, and publish them as PDF minigames with a counter sheet. The only thing I imagine is totally verboten is reprinting the rules for ACTA.
All you really need is the ACTA rulebook; the PDFs serve as fluff and fleet lists. It's a fine system, why not let it expand more? Heck, I imagine the system could be used to model aircraft battles as well as space/naval battles.
Some of this has already been done with the fan rules for other sci-fi universes and fan-expansions on the B5 universe. It is not without precedent.
Of course, I suppose I should ask what Mongoose's elite cadre of lawyer-ninjas say about this?