Off the top of my head I can think of three option that are not that difficult to implement.
First option, You could add a step type of the <none> variety (instead of a labview, labwindows, dll, .net, etc.). I would suggest a numeric limit test if the variable is a number. Then ,on the edit limit menu of the <none> numberic limit test, change the data source to your variable. You can apply limits if you wish (force the status to a pass if you don't want to affect the pass/fail of the sequence with this step)
Second option, Each step has a output string buffer that you can add any text you want. It is step.result.ReportText and can be set in the expressions tab of any step. Formart your variable to a string and add it to the appropriate step.
Third option, Use the sequence file callbacks for the reports. This is a bit more advanced if you are new to teststand. I would suggest researching sequence file callbacks because to describe them here could get too involved. The callbacks allow you to change the way the current SequentialModel.seq executes and there are specific callbacks for customizing reports.
Hope this helps