There are no commercially available, stand-alone riding snow blowers available as of August 2015. There are many attachments available to turn a riding lawn mower or tractor into a riding snow blower or snow plow, however.
The Johne Deere, Craftman, Huskvarna and Snapper companies all make a variety of riding lawn mowers and tractors and all also offer snow blowing attachments. Removable, collapsible cabs made of heavy-duty vinyl are also available for lawn tractors to make the time using it for snow removal more comfortable. Prices vary depending on manufacturer and the size of the lawn tractor and snow blower attachment.