You can put just about any control in a RadContentTemplateTile: http://docs.telerik.com/devtools/aspnet-ajax/controls/tilelist/tiles/contenttemplate-tile.
Note that its default size is quite small and is not likely to suffice for so much content. Thus, I advise that you consider a simple <div> container that you can style according to your preferences.
Very complex content also defeats the purpose of the tile, as its intended use is for short messages. For example, complex functionality on controls inside the content template may cause issues with peek template animations and / or click handlers.