A workaround is to have the tile list use the Default skin and change the tiles classes with JavaScript in the OnClientTileDataBound event

			<asp:ScriptManager ID="Scriptmanager1" runat="server" />
			<telerik:RadSkinManager runat="server" ID="rsm1" Skin="mySkinName"></telerik:RadSkinManager>
			<telerik:RadClientDataSource runat="server" ID="RadClientDataSource1" PageSize="8" AllowPaging="true">
				<DataSource>
					<WebServiceDataSourceSettings BaseUrl="http://demos.kendoui.com/service/">
						<Select Url="products" DataType="JSONP" />
					</WebServiceDataSourceSettings>
				</DataSource>
			</telerik:RadClientDataSource>
			<telerik:RadTileList ID="rtl" runat="server" RenderMode="Classic" TileRows="3" SelectionMode="Multiple" OnClientTileDataBound="createTile" OnClientTileClicked="tileClicked" EnableEmbeddedSkins="false" Skin="Default" ClientDataSourceID="RadClientDataSource1">
				<DataBindings>
					<CommonTileBinding TileType="RadContentTemplateTile" DataNameField="ProductID" DataTitleTextField="ProductName" DataBadgeValueField="UnitPRice" Shape="Square" />
					<ContentTemplateTileBinding>
						<ClientContentTemplate>
					<div style="height: 150px; background-image: url('#= ProductName #');">
						<div style="padding: 5px 8px 3px 8px;">
							<div>#= ProductName #</div>
							<div style="font-size:0.8em; width: 134px; word-wrap:break-word; padding-bottom: 8px;">#= UnitsInStock #</div>
							<div class="field pad" >
								<img src="images/email.png" title="Can be emailed">
								</img>
							</div>
							<div class="field pad">
								<img src="images/SMS.png" title="Can receive SMS">
								</img>
							</div>
							<div class="field pad">
								<img src="images/noentry.png" title="Has a restricted password">
								</img>
							</div>
						</div>
					</div>
						</ClientContentTemplate>
					</ContentTemplateTileBinding>
					<ClientTilePeekTemplate>
				<div style="height: 150px; background-image: url('styles/#= ProductName #/images/large/user.jpg');">
					<div style="padding: 5px 8px 5px 8px; width: 134px; height: 140px; background-color: azure;">
						<div>#= ProductName #</div>
						<div class="field" style="font-size:0.8em; width: 100px;">#= ProductID #</div>
						<div class="field" style="font-size:0.8em; width: 34px; text-align: right;">#= ProductID #</div>
						<div class="field" style="font-size:0.8em; width: 100px;">#= ProductName #</div>
						<div class="field" style="font-size:0.8em; width: 34px; text-align: right;">#= ProductName #</div>
						<div class="field" style="font-size:0.8em; width: 100px;">#= UnitPrice #</div>
						<div class="field" style="font-size:0.8em; width: 34px; text-align: right;">#= UnitPrice #</div>
						<div class="field" style="font-size:0.8em; width: 100px;">#= UnitsInStock #</div>
						<div class="field" style="font-size:0.8em; width: 34px; text-align: right;">#= Discontinued #</div>
					</div>
				</div>
					</ClientTilePeekTemplate>
				</DataBindings>
			</telerik:RadTileList>
			<script>
				function createTile(sender, args) {
					var tileElem = $telerik.$(args.get_tile().get_element());
					tileElem.removeClass("RadTile_Default").addClass("RadTile_mySkinName");
				}
				function tileClicked() {
				}
			</script>