To me, an ideal B-sides album would go as such:
1. Mad The Swine (3:20)
2. See What A Fool I've Been (4:32)
3. Funny How Love Is (edit; 2:51)
4. Flick Of The Wrist (edit; 3:17)
5. Tenement Funster (edit; 2:58)
6. Lily Of The Valley (edit; 1:38)
7. I'm In Love With My Car (edit; 2:50)
8. A Human Body (3:42)
9. Soul Brother (3:37)
10. I Go Crazy (3:42)
11. Blurred Vision (4:43)
12. A Dozen Red Roses For My Darling (4:42)
13. Forever (3:22)
14. Chinese Torture (1:45)
15. Hang On In There (3:43)
16. Stealin' (4:00)
17. Hijack My Heart (4:10)
18. My Life Has Been Saved (3:15)
19. Stone Cold Crazy (live) (2:14)
20. My Melancholy Blues (live) (2:54)
21. Lost Opportunity (3:52)
22. It's A Beautiful Day (edit) (4:02)
23. Rock In Rio Blues (4:33)
The inclusion of 'Chinese Torture' may be slightly dubious, as I don't think it was a B-side, but this all fits on one CD. 'Funny How Love Is', too, could be easily replaced, as it was on the 1988 CD single reissue of 'Seven Seas Of Rhye', and though 'Flick Of The Wrist' is technically an A-side, it hasn't appeared on any compilation thus far.
If you wanted to get technical, you could substitute those three tracks in lieu of 'Gimme The Prize (instrumental remix)', which was included on the 'No One But You' CD single, and 'Queen Talks', which is a waste of time yet was released on 'The Show Must Go On'.