One of the most interesting and successful work in this realm comes from the Lex Bronkowitz Orchestra, specifically on their recent album Strictly Gravy (nl fzio CD). What's really good about this outfit and this set? They play a few that have gotten plenty of attention, "Big Swifty" and "Mr. Green Genes," for example. But then they tackle some that have not been often heard, like "Uncle Remus," "Andy" and "rdnzl." And there are medley combinations (something Zappa himself favored in live settings) that work quite well.
The arrangements are by Lex. And they follow best practices, to my mind. They freshen up the sound and adapt it to the group at hand (Lex on guitar, Katharina Debus on vocals, plus mallets, drums, bass, and a guest horn section of sax, trombone and trumpet). They do justice to the music by staying very close to the spirit of Zappa's musical thinking, yet extend that for today.
Lex plays guitar very nicely, and can and does solo in a post-Zappa mode, as effectively as anyone playing today. He does something with the irregularity of phrasing and that soulful melodicism, both Zappa guitar hallmarks, and he even gets a Zappa-esque sound from his guitar. Yet it too is an extension with a creative, original component that is a joy to hear.
Finally, the entire band is very good. Everybody can play, Katharina has soul and finese. She makes all she sings seem right, but also seem right for HER.
This one clocks in at 36 minutes. Surely no second is wasted time. In fact this is one of the most invigorating and satisfying Zappa tributes I've heard. It stands on its own as excellent music in its own right. Now that's very cool!