It would be great to have an auto-save feature in Visual Style Builder for when/if VSB crashes or quits improperly and theme wasn't saved.  

See my forum post for more information, at: 
http://www.telerik.com/forums/visual-style-builder-frozen---does-it-do-any-auto-saving

Resolution: Under Tools>>Settings in VSB there is an option to enable/disable saving auto recovery info and the interval at which this info is saved. The auto recovery data is saved as a .tssp file in the C:\Users\<username>\AppData\Roaming\VsbRecoveryData\ folder. The mechanism is as follows every X minutes the file is overwritten with the current state of the theme in VSB. If VSB is closed gracefully or the theme is unloaded the auto recovery data is deleted. If VSB crashes the data in the auto recovery folder remains. On the next VSB start this folder is checked for content and if there is any the user is offered a choice to load this content.