This might be beyond the capabilities of JIRA, so before pursuing it further, that's what I'd like to try and find out:
Is it possible to create a scripted post function - I'm thinking it would have to be Jython or Groovy - that could query a SQL or Oracle database using username/password/dbserver info specified by a reporter from required Custom Fields and return a value from that database into another custom field? It's essentially a data integrity check that could save 1.25 person hours weekly, and would be very slick if it could be automated through JIRA.