Best approach (what we're doing actually) is to create an image for each plan (could be very basic such as some text on a white background), then use CBSubs Plans Image integration (configure within your plans what image to associate with a plan), which is a field that can be displayed on userslists, profiles, etc.. Alternatively you'll need to create a new CB field (text?) and update it using CBSubs Fields with which plan they've purchase, but this would only hold a single plan.