I don't have a specific example, however, I think what you want to do is possible, but perhaps not straight forward.
An approach to try would be to offer the user a multiselect list box with the fields of your query available for them to select. Using item selected you could pass the field names to the report. Depending on your version of access this could be difficult or very easy.
You could then make the various fields visible to show the records selected.
However, this will give you a report that has all text boxes displayed in an ad hoc manner.
I have been able to do the following in height but not so sure about width, but you could try a few experiments to see if it works.
In design view of your report size the text boxes so they combine to leave no white space between them at all. Go through and write down the widths pertaining to each one. Then make them all a sliver thick, so they all end up on the left hand side of the screen.
Then as you make them visible try altering the width to your design width.
I think this sort ofapproach will get you started.