Ok, now I know what you're looking for!
SaintDog has not released the mod you're looking for. You can find his explanation at
this link.
However, what you're looking for is similar in nature to [Release] Category Backgrounds template mod [
link] and could be modified to work with your postbit.
What he's done (and I hope I don't get accussed of ripping here

) is to create a table with the following:
1. First cell includes the left image
2. Second cell includes a background image (see link above for the template mod) and the post title
3. Third cell includes the right image
4. He repeats the the similar process for the footer
I can see why SaintDog hasn't relased this just yet. There's a lot of options here in this template mod depending on how your postbit is configured. Plus, you have to have custom images.
I hope that helps!