I was cruising YouTube and stumbled upon this video of this guy playing Rush's YYZ on his bass. He didn't do a perfect job, but he was danged good. Intrigued, I checked out his other videos. Most of his other videos were RHCP covers. They were awesome. He really nailed most of them. His bass is hooked directly into his computer and sounds tonally different than the songs, so it's clear that it is really him playing. You can hear his bass perefectly and I think his videos could be used as a tool to practice with. Also, you can possibly get a bet feel for what Flea is actually playing.
Here is a link for one of his videos.
http://www.youtube.com/watch?v=Y9054NsctOs
This is him playing Audioslave's One and the Same
His name is Felipe Solano. You can put his name in YouTubes (Or Googles) search directory and you can get access to the rest of his videos.
Actually, I think anyone of any skill might enjoy listening to this guy and his covers.