This project is a Drupal 7 module that contains an example of an MVC-ish way of setting up a custom content block.
The idea is for this to be the bare minimum code to escape from Drupal and start writing the code that does the thing.
The module has just enough code to setup a block, a template, and a data model and put them all together. With this as a starting point, all you have to do is setup your data model and then use it in the template with whatever markup you like. Then you can add your block to a region or panel or view or whatever.