Yes Interactive Intelligence does have an integration for Siebel CRM. There are two integrations components. One allows for embedded call controls, screen pop, click to call, and screen transfer within the Siebel web desktop. The other component allows for data dipping from the IVR through Siebel's Data Object repository (Business layer) which allows for automating creates, reads, updates, and deletes of Siebel Objects.
You can find more information if you have access to our product portal here:
https://my.inin.com/support/products/integrations30/pages/Siebel.aspx