FUCKIN A!! I've seriously been looking for this song for about 10 years and last night, I finally found it. While recording Midnight Vultures in the late 90's, there were rumors that Kool Keith (who Rippy and I were obsessed with at the time) dropped by Beck's studio in Los Angeles and jammed with him for a day. I bought every possible single for MV and subsequent albums hoping it would show up as a B-side. No luck. Gave up a few years back and happened to remember it recently. Went looking deep in some superfan Beck sites and found it. Here is some other info on the sesh:
Sometime during the Midnite Vultures recording sessions in 1998-1999, Beck hooked up with rapper Kool Keith and recorded a couple of tracks. As he recalled in NME, "When we hooked up, we immediately wrote three songs together. We were completely on the same wavelength. Whatever our music planets, we're definitely on the same orbit."
"California Rodeo" is the name of one of these recordings. In July 2003, the lyrics showed up on Beck.com, and the song began to circulate among Beck fans in 2006. The song is indicative of when it was recorded, and has the full-on Vultures sound. Kool Keith gives shouts out to Beck and DJ Swamp (who was also on the track) in his long freestyles. Beck does the chorus part.
Here's the song if you want to jam it before DLing: