We've received requests to create a variant of Call AI that specializes in SMS. The idea is simply to use outgoing SMS instead of outgoing calls as a criteria for selecting contacts to the widget. Also, when contact is tapped an SMS editor (to selected person) will launch, instead of contact info screen.
This has been in the works for a while, and is now approaching release status. Here's a screenshot as a teaser. Stay tuned for release announcement soon.