We had a question on the support forums about modifying the database used for Workflow Studio, which defaults to 'WFDB'. All the SQL scripts are provided for you in the Workflow Studio install, and we anticipated our customers wanting to have multiple databases on a single server or just changing the name from the default 'WFDB' name. In fact, if the SQL Admin wants more control they can customize as much as needed.

I wrote up an article to cover the process:
http://community.citrix.com/display/wf/Customizing+Your+Workflow+Studio+Database

If anyone tries this and runs into problems let me know