Great write-up JabbaJohnL!
I think the most possible and toyetic large TPM ship left is the Radiant VII (Republic Cruiser that Qui-Gon arrives in the Trade Federation Ship on).
This ship (Blockade Runner reminiscient) is also seen a lot in Clowe Wars (with added cannons to defend it - as TPM version in the film was likely unarmed).
Made with removeable weapon installations that can make the ship film accurate or CW / Kid friendly, the out-of-scale version could be fun as a large (Class 3 BMF) vehicle - provided it's not TOO small - at least Royal Starship sized.
The return of the Royal Starship seems like a cheaper, more likely way to go. They can retool it a little and make their cost cheaper by removing some of the extras and cool electronics.
The ship hasn't seen a release in a decade and was TPM's first large vehicle:
ANH: Falcon, BMF, X-Wing, TIE Fighter
ESB: AT-AT, BAT-AT, Slave-One, AT-ST
ROTJ: Imperial Shuttle
TPM: Royal Starship, BN-1, MTT
AOTC: Republic Gunship, AT-TE
ROTS: ARC-170, TurboTank
Of course, I'd prefere the Radiant VII Republic Cruiser with removeable CW weapons. I bought 2 Royal Starships ten years ago and am not in the market for any. But for kids and nOOb's, the Royal Starship interacts with more of the main characters.
To market the Radiant VII, the box must feature Qui-Gon, Obi-Wan, the larger Class-2 Droid Fighters, Battle Droids, Destroyer Droids, and Daultay Dofine, Nute Gunray, and Ruune Haako - and maybe include an exclusive Tey How, or better, the Radiant VII captain and pilot (Silas Carson).