Hi,
Our Product Slider module is an the extended version of official Virtumart Product Module, as you might now, this doesn't available in the official one as well. Eliminating parent product and showing only child products, would require a strong structure change. I am pretty sure that, none of the modules around for product listing can handle this by default. Because things will get messed up if you have a product that doesn't have any child product. I understand your estore doesn't have any parent product at all, but i am sure you are the only one who designed his/her virtuemart by this method. Anyway, what you are asking is very specific scenario and It will require some customization. I am not quite sure if it is possible though, because it doesn't sound doable to me.
Cheers.