FalconFour,
I've had the exact same frustrating issue you experienced with the integrated graphics chip (Intel 4400HD) that was part of my new Dell 3647 small footprint PC that I'm using as a media center with an older Sony KDF-55WF655. This TV supports 1920x1080i, but using this resolution with the Intel video chip results in overscan as you have experienced as well. This new Dell replaced an older HP Media Center that had an Nvidia chip that included overscan compensation in the driver, but the intel does not at this resolution. Why Intel has not solved this issue for interlaced resolutions is frustrating.
I accidentally discovered a solution, that may (or may not) work for you.
First I downloaded the most current driver from Intel.
I then set the resolution at the highest resolution that was not interlaced and by doing so, I could then take advantage of the Custom Aspect Ratio settings in the Intel driver. For some reason, once the intel driver sees a resolution that is interlaced, the Custom Aspect Ration settings located under the Display General Settings no longer is visible. Setting a lower resolution that is not interlaced allowed me to then set the Custom Aspect Ratio that eliminated the overscan. But, this was not ideal as I had to settle for a lower resolution than the 1920x1080i.
I was ready to accept this lower resolution compromise when I discovered, by accident, that I could preserved the Custom Aspect Ratio at the higher resolution. I switched to the higher 1920x1080i resolution (after I had set the Custom Aspect Ratio using lower resolution non-interlaced). The key was to switch to the higher resolution not using the intel control panel. Instead right click on desktop, select Screen Resolution, click Advanced Settings, click List All Modes, and pick the higher 1920x1080i. Miraculously, it kept the Custom Aspect Ratio and I no longer have overscan issue.
Let me know if this work for you.
BTW- don't go back to the intel driver settings, as doing so will undo the Custom Aspect Ratio at the 1920x1080i resolution.
Pat