UPDATE:
Sumo Digital representative SumoRex at the SEGA Forums has made a couple of posts in a topic there regarding this rumor.

lol …youz guys!
It’s true we *are doing a sequel. No! no! Wait …don’t get your panties in a bunch. I’m kidding.
Or am I?
I definitely am.
or is that the lie?
or this?

Rumours totally crack me up! lol

Official line:
“I can neither confirm nor deny the existance (nor absence) of the truth or a lie in the above statement”

Is that clear enough for you? If that doesn’t stop these pesky rumours one way or the other nothing will!

/UPDATE END

[youtube]http://www.youtube.com/watch?v=Fx4lWZzPk4c[/youtube]

According to the above 18th Feb 2010 report from WatchMojo Sonic & SEGA All-Stars Racing is getting a sequel and that’s not all, they say SEGA have hinted they are saving characters from other games in their library for this sequel. WatchMojo also say SEGA Miles are also used to unlock artwork in the game which as you know is nowhere to be seen in the game, maybe a scrapped feature? (Thanks to Veritech Guardian at the SSMB for pointing that bit out) Whether any of this is true or not is unknown so we advise you to take it with a grain of salt.

Would you like a sequel with characters from other SEGA games? Sound off in the comments.