As of the latest “code push”, Variable Flow now has support for customized comment views (finally!)
I tried to keep to the simple style of the rest of the layout on the comment views, as well as including enough markup to hook your custom CSS rules onto. The comments are marked up just like entries, but they live inside a list of class comments so you can apply special CSS rules to them if you like.
In order to avoid startling people who are already using the layout, the customized comment views are off by default for this layout. You can switch them on using a new option at the end of the “Presentation” tab in the customize area. (As with all layouts, this option isn't available to users with Free Accounts. Sorry!)
I may have to make a few adjustments to the default presentation of the entrypage once it becomes clear how people are using it and if there are any bug reports. For now, enjoy!