Virtual Sonic - Actually Sonic X-treme Music?
Believe it or not but I think that some Sonic X-treme music actually exists today; the problem is it's right under our noses... You'll notice Howard Drossin was in charge of Sonic X-treme's music. Mr. Drossin has such credits as doing music for Sonic 3, and Sonic & Knuckles. Now, Sonic X-treme was canned in 1996/1997. In that SAME YEAR, Howard Drossin released a "Sega Tunes" CD under the name of "Virtual Sonic". Subtitled with, "Enhanced Music Inspired by the Worlds of Sonic". There were 12 tracks on the CD; some were remixes, others were completely original compositions.

I personally believe it was more than a mere coincidence that this CD was released (Copyright Date is 1996) around the same time Mike Wallis pulled the plug on the Sonic X-treme project. Tracklisting is as follows:

1 -- Chaos Jam
2 -- Knucklemania
3 -- Battle of the Badniks
4 -- Boss Opera
5 -- Return to the Toxic Caves
6 -- Sonic and Knuckles Theme
7 -- Robotnik's Revenge
8 -- Metal Sonic
9 -- Sandopolis
10 - Spinball Theme
11 - City in the Clouds
12 - Sonic Triumphant

Tracks 2, 5, 6, and 10 are remixes of well known tunes (Don't be fooled by the name "Sandopolis" - it bears NO musical resemblence WHATSOEVER to the S&K Sandopolis). I've composed what I believe some of these tracks might've been used for:

1 -- Chaos Jam - Intro Sequence to Sonic X-treme, (and Titlescreen Music?)
2 -- Knucklemania
3 -- Battle of the Badniks - Boss Sequence: Fang the Sniper
4 -- Boss Opera - Boss Sequence: Generic Boss
5 -- Return to the Toxic Caves
6 -- Sonic and Knuckles Theme
7 -- Robotnik's Revenge - Boss Sequence: Final Boss
8 -- Metal Sonic - Boss Sequence: Metal Sonic
9 -- Sandopolis - Level:Red Sands Zone
10 - Spinball Theme
11 - City in the Clouds - Level:Galaxy Fortress Zone
12 - Sonic Triumphant - Ending Sequence

While this is only speculation, I believe that such a thing might have some form of truth in it. It's just such a huge coincidence. If you would like to listen to these songs, please give TeamArtail a look. They have low-quality streaming versions of each song and information on where you can purchase the "Virtual Sonic" CD.