Of course you can blend channels with the right Cisco product sets.
You could install EIM setting up the email channel. This is normally specified as an interruptible channel, but you can change it. You won't be set not ready for voice when an email arrives, but you won't get a call from the queue or an email from the email queue until you complete the current task.
I'm not sure if this is what you are asking.
Regards,
Geoff