Absolutely, Rotel has rack ears available for many of the 15 series products, either included or available as an optional accessory. Talk to your authorized dealer for details on this.
For other Rotel products such as the 12 and discontinued 10 series, rackshelves from manufacturers such as Middle Atlantic are often an alternative. The Middle Atlantic RSH series rack shelves offer custom faceplates to provide a seamless look when using a rack shelf with many Rotel products.