marketpress and post_thumbnails support

At the moment if you add a product with images but forget to choose a feature image then the product has a blank space instead of an image when its in the listing for the store or the global listing.

Is there any way of adding or altering code for market press to use a fallback image, or ideally not to rely on the feature image at all but to use the first uploaded post image instead.

Ive tried "get the image" plugin, which works for some pages by adding it to the template files (simplemarket template) but it wont work for products in a list or grid.

Ive also tried a couple of other feature image fallback scripts which do the same thing as "get the image".

looking through the marketpress.php script I think that all themes for marketpress must include post_thumbnails support? What happens if I use a theme without post_thumbnails support? Will any images show with the products in a list view?