Anyone Added A New Carrier With Realtime Rate Calcs

Anyone ever added a new carrier that has a realtime shipping rate retrieval capability? I have seen the posts regarding a new carrier with the tracking URL. But what we're looking for is on the Checkout side.

We use unishippers because they get better rates from UPS. But, we have to hook to the unishippers real-time rate calculations system.

It looks like we need to create a new carrier which is straightforward. But then we need to create a template with the appropriate fields needed for our account info with them (similar to ups.tpl). And then we get really down in the weeds in trying to match up fields and connect to the unishippers API. Plus, now we feel like we're modifying the database and that is not a smart idea.

Has anyone done this? Or would anyone like to quote to create this?