Jet Set Radio future was the latest game in the franchise.
It was made by Sega people called Smilebit.
Since JSRF they've made a few Japanese football games and Panzer Orta which is cool
One of the people who did the music for JSR and JSRF also did the music for Sonic Rush. If you liked the style you might wanna download the soundtrack for Sonic Rush as its really, really good. (And Sonic Rush 2 is coming out at the end of the year!!)
I would LOVE another JSR game but theres no plans to make another atm.