I am looking to do something similar. I have considered an outside end point that interacts with the Method API. We use RingCentral as a phone system and may be able to use their CTI (softphone) product to trigger our search.
Please share any progress.
Ideally, we would be able to do something like many other CRM's do with the leading phone systems and would launch the customer record on the match of the incoming caller ID. Is that what you are after?