I would imagine you have read them, but for others possibly interested in the story, there are two interesting books on the subject: The Saint and the Devil (The story of Joan of Arc and Gilles deRais) by Frances Winwar (1948), who looks to have done a great deal of research, and the much lighter, more contemporary Gilles and Jeanne by Michel Tournier (1983). If you haven't read the former, it has an extensive bibliography that might be helpful to you.
So for me, yes, I would think that a very interesting topic (and if he is indeed guilty of the murders, or whether he met his end for his previous staunch support of d'Arc). It would be wonderful to have an adventure game including Joan, where reflex action isn't necessary, and the complexities of the characters were revealed (no small task, I am sure!).

Actually I haven't read them, because the idea of Gilles de Rais as a subject just popped in my head while answering the forum...

Ah, well it was a good one!

I love historical settings... I wish someone would write an adventure set in the Regency period in England, thats my favourite read

I love historical settings as well Tigger, especially history's mysteries sort of thing. All this talk of pirates got me thinking that it would be great to have an adventure game on Grace O' Malley, pirate queen.