From the Windy City, there is an a female, a cappella, “corporate entertainment” quartet that calls itself Route 66.
Route 66 reminds me of the Andrews Sisters, but it also sings more contemporary pop songs such as Queen, James Taylor and Creedence Clearwater Revival (Mp3 samples of Route 66’s songs are here). I didn’t see Bobby Troup’s “Route 66” among the samples, but it is among the group’s repertoire.
According to its history, Route 66 started in 1994 in the Netherlands and eventually moved to Chicago. Don’t look for the group to go on tour; it sticks close to Chicagoland.
Here’s a video clip of footage from Route 66’s gigs (embedding of this video wasn’t allowed).