I think it's awesome when Blues Traveler does cover tunes - My Sharona would be great, Creep is very good, Imagine is awesome on Live/Fall, What I Got is good, and Whammer Jammer would be the best! I'd love to see Johnny wail that one.
Not such good cover ideas - anything by the Dead. Sorry, nothing personal, I just can't stand that stuff.
One last thing....the bass line on Creep would make the late/great Bobby Sheehan proud.