Using Texture Swatches (thumbnails) Inside A Gui

Is it possible to gain access to the thumbnails/swatches maya generates for file nodes inside a custom GUI?

I'm working on a script that asks the user to choose a material, and i would like to present as part of that choice a representation of the file node.

thanks.

Yup, swatchDisplayPort is the command you're after.

Also if they are still on disk use visor