It's available on "Greatest Karaoke Hits". The original recording, minus lead vocal. Available online from these retailers and more:
CD Universe ($42.39) link
Amazon.com ($51.49) link
HMV Japan ($31.85) link
CD Japan (listed as out of print.. hmm) link
QueenOnline Shop ($35.98) link
It's a great set of 32 karaoke remixes of Queen hits, from the original master tapes. Not a cover band. There's also a DVD available with the original videos and 3 additional bonus tracks. You'll find info linked from the Queenonline listing above.
Thanks for shopping Queen Productions. What we do best is take your money. :)
There's also an instrumental version (bloody good one too) on the soundtrack to "Queen - The eYe". Unfortunately neither that, nor the Karaoke version may be shared as they are both official releases.
Best regards,
V.