I was just browsing about classes and "OO in VB", and I found something useful for you too:
Forms can set other form's properties.
So you could either create a hidden text-control in the calling form. Then, the modal show dialog set's this hidden text's text-property when everything is done.
Or, you could use the Form.Tag property. AFAIK this is a free usable String-Property, that has no purpose at all and that you can set at will...
Now you should've plenty of opportunities.
But I agree with you, that for people who do really know (and support) the true OO paradigma and who have some experience in classing etc, this stupid cheap and non-conform non-consquent VB sucks a tiny bit....
Still like it