Song List: Covers "Chain"

The New York Times (registration required) writes about bands covering very recent songs (and even some songs that the original band hasn't released yet). I know some of my friends are disturbed by this trend but I likes it. Scissor Sisters do a great version of Franz Ferdinand's "Take Me Out" (mentioned in the article). REM covered Interpol's "NYC" nicely.

What is the longest "chain" of cover acts? (Artist A covers Artist B who covers Artist C...can't repeat an artist.) My first attempt (with help from The Covers Project):

1. Richard Cheese -> Beck ("Loser")
   
2. Beck -> Flaming Lips ("Do You Realize?")
   
3. Flaming Lips -> White Stripes ("Seven Nation Army")
   
4. White Stripes -> Dolly Parton ("Jolene")
   
5. Dolly Parton -> Johnny Cash ("I Still Miss Someone")
   
6. Johnny Cash -> U2 ("One")
   
7. U2 -> Patti Smith ("Dancing Barefoot")
   
8. Patti Smith -> Bruce Springsteen ("Because The Night")
   
9. Bruce Springsteen -> Byrds ("Ballad Of Easy Rider")
   
10. Byrds -> Bob Dylan (many, many songs)
    
11. Bob Dylan -> Townes Van Zandt ("Pancho And Lefty")
    
12. Townes Van Zandt -> Rolling Stones ("Dead Flowers")
    
13. Rolling Stones -> Bobby Womack ("It's All Over Now")
    
14. Bobby Womack -> Neil Diamond ("Sweet Caroline")
    
15. Neil Diamond -> Leonard Cohen ("Suzanne")
    
16. Leonard Cohen -> Pee-Wee King ("Tennessee Waltz")