You can create some new propertysettings for the TinyMce editor like this.

    [ServiceConfiguration(ServiceType = typeof(PropertySettings))]
    public class NoToolbarEditorSettings : PropertySettings<TinyMCESettings>
    {
        public override Guid ID
        {
            get { return new Guid("86414FC8-0F1F-4A48-B6B6-04FE98E41488"); }
        }

        public NoToolbarEditorSettings()
        {
            DisplayName = "Editor without toolbar";
            Description = "This will show a TinyMce editor without any buttons";
            IsDefault = false;
        }

        public override TinyMCESettings GetPropertySettings()
        {
            var settings = new TinyMCESettings();
            settings.ToolbarRows.Add(new ToolbarRow(new List<string>()));
            return settings;
        }
    }

Make sure IsDefault=false 

Not configuring or clearing the ToolbarRows will not work, so insert an empty row. 

And assign these setting to the TinyMce property in question

[PropertySettings(typeof(NoToolbarEditorSettings))]
public virtual XhtmlString Text { get; set; }

Now you have an editor without a toolbar.