Yep, I wanted the same thing on our upholstery site and found the same problem, no existing token for it. So i modified the source to add one in ;-)
If you have the source you can add one too. The modification is done in ASPDNSFCommon\parser.cs (the lines without the plus in front are existing lines you should be able to find in the file, the lines with pluses you will need to add, without the pluses of course)
Code:
tmpS = ShoppingCart.NumItems(ThisCustomer.CustomerID, CartTypeEnum.ShoppingCart).ToString();
m_DynamicTokens.Add("(!NUM_CART_ITEMS!)", tmpS);
+
+ //USERMOD - add cart subtotal
+ ShoppingCart cart = new ShoppingCart(SkinID, ThisCustomer, CartTypeEnum.ShoppingCart, 0, false);
+ tmpS = ThisCustomer.CurrencyString(cart.SubTotal(true, false, true, true));
+ m_DynamicTokens.Add("(!CART_SUBTOTAL!)", tmpS);
+
tmpS = AppLogic.GetString("AppConfig.CartPrompt", SkinID, ThisCustomer.LocaleSetting);
m_DynamicTokens.Add("(!CARTPROMPT!)", tmpS);
after recompiling the Common DLL you should have a new token available to you called !CART_SUBTOTAL!
Hope that helps!