Media player and iTunes can crossfade in the settings. I don't know exactly how on iTunes but on media player you just go to
Now playing>
Enhancements>
Crossfades
Set it to max or whatever is ten seconds, with this playlist
1. Airbag (OK Computer)
2. 15 Step (In Rainbows)
3. Paranoid Android (OK Computer)
4. Bodysnatchers (In Rainbows)
5. Subterranean Homesick Alien (OK Computer)
6. Nude (In Rainbows)
7. Exit Music (For A Film) (OK Computer)
8. Weird Fishes/Arpeggi (In Rainbows)
9. Let Down (OK Computer)
10. All I Need (In Rainbows)
11. Karma Police (OK Computer)
12. Fitter Happier (OK Computer)
13. Faust Arp (In Rainbows)
14. Electioneering (OK Computer)
15. Reckoner (In Rainbows)
16. Climbing Up The Walls (OK Computer)
17. House Of Cards (In Rainbows)
18. No Surprises (OK Computer)
19. Jigsaw Falling Into Place (In Rainbows)
20. Lucky (OK Computer)
21. Videotape (In Rainbows)
22. The Tourist (OK Computer)
It's just two albums in numerical order. It fits seamlessly like one super-album or, and some tracks even blend like one song. Coldplay never did shit like that. Fuck you Coldplay.