The short answer is no. But you can add custom fields to track things like in or out of warranty, reference numbers, approval and so on.
Return Types are to some degree automated. When products are received, the return automatically goes to the next status based on the type. Also, return types are highly integrated with serial number verification. The verification checks each SN against the status of the return they are on to determine if a SN is valid.
These and other reasons contribute to the lack of customization. But in the future we do aspire to add more custom workflow options.
*For special circumstances, note that there is the "Advanced Replacement" option for shipping a product before receiving the old one back. There is the "Prepaid Label" option for emailing or sending a prepaid shipping label to the customer. And the "Ship Only" return type can be used when shipping a replacement without getting one back. Likewise the "Receive Only" is handy for eval returns and the like.