Anyone have information on Melbourne House's cancelled Transformers sequel?

In 2004, Atari (Infogrames) subsidiary Melbourne House (now Krome) launched Transformers for the PlayStation 2. The title was an tie-in for the then current generation of Transformers media, known as the Unicron Trilogy. Despite being only developed in 12 months, the game was technically and was at the time the best received Transformers video game.

Looking up some information on the game reveals that Melbourne House were looking into making this more than just the one-off it became. It seemed there was some interest in porting the game to PSP and doing a proper followup. The latter is expanded upon by the Transformers Wiki, which claims a sequel was cancelled just a few months into development. I was really active in Transformers fandom at the time and I want to say someone with the username "Natalie" (Food for Natalie??) claimed to be a MH employee and shared the grim news. A sequel is off handily mentioned in an Unseen64 post about another cancelled Melbourne House game:

It's been more than 10 years since the game's cancellation. Has anyone been able to unearth any production art, character models, etc.? The first game was developed in just a year, so the sequel only being a few months in the can could've meant decent progress.