Alas, the few people who do have access to the prototype don’t share our point of view; thus, there is no ROM dump available anywhere (or at least I couldn’t find one). That’s what I was trying to imply with my previous post. If you have better luck, please let me know.
Back on topic: another famous cancelled game is Sonic X-treme, but what some of you may not know is that fans found the source code for one of the game’s early builds and got it to run on modern Windows. It’s a very early build (comparable to the prototype of Super Mario’s Wacky Worlds for CDI): there don’t seem to be any enemies, you can’t collect rings, and you have to do multiple mid-air jumps to get around some of the levels, but it’s playable. Thread is here for those curious.
As for lost media, there’s Dragon Hopper for the Virtual Boy. Unlike Bound High or even Katakis 3D, there’s no known prototype anywhere, with the only evidence of its existence being E3 footage and other promotional material (and even that much is a rare find). From what I’ve read, it looks like it could’ve been a pretty fun game; oh well.