Hello @tsw,
Regular (non-advanced) SmartObjects get created in the K2 database which cannot be changed, so in a sense I believe the answer here is no. However, you can create some relativly simple SmartObjects by creating tables in your SQL database and then generating SmartObjects based off these tables. This will create SmartObjects that look fairly similar to SmartBox SmartObjects or "regular" SmartObjects. All you need to do is track down your Service Instance in management, then select the 'Generate SmartObjects' option, and select the tables you would like to create SmartObjects for.
Thanks,
Samuel