System notes searches - any help???

Hello everyone,

I would like to be able to do a saved search that would look to the system notes for a particular custom record on our customer records, and return a listing of customers where the "old value" for the field is equal to one thing and the "new value" for the field is equal to something else.

For example, on our customer record, we have a check box field called "Is this a demo," which allows us to tag certain customer records as demo customers in the case we set them up with a demo/trial account of our software product.  Upon purchasing our software, we then uncheck this field.  I would want to be able to do a search into the system notes for this field to return the results of all customers who went from "is this a demo" = True to "is this a demo" = False, and to pull in transaction information.