I remember reading a list of cancelled games for the Dreamcast, and this was one of them. I'd be interested in any information anyone would have on it, though I'm pretty sure nothing about the game ever got off paper. Care to discuss?
Although never confirmed, I first saw the working title Sonic & Knuckles RPG mentioned in a late 2000/early 2001 promotional leaflet. I've heard this was a codename for what later became Sonic Heroes, and considering the teamplay element I've no reason to doubt such claims - even though the end product was as far removed from that genre as may be possible!
..hold on.. ...wait for it.. ..must.. resist.. ...SONIC HEEEEEEEEROEEEEEES! SOOOOOONIC HEEEEEEEEEEEROOOOOOOES!
I have a copy of Official Dreamcast Magazine (UK) it was an issue reviewing Sonic Adventure 2. There was a small column sporting rumours of the newly announced Sonic and Knuckles RPG, which means it couldn't possibly be Sonic adventure. I'll try and get a scan up soon.
Ah, I looked through some old issues and Sonic Adventure was mentioned as "Sonic RPG", not Sonic & Knuckles RPG. Although some people called it Sonic & Knuckles RPG back then too. There are some links to the two online if you google it too.
I first noticed Sonic & Knuckles RPG listed as a working title in a leaflet for Dreamcast games expected by early 2001, if that helps. As for Adventure having the development name of Sonic RPG, this is news to me. However, it was definitely known as Sonic World at one point.