Not sure what the plans are for the ecommerce module and this. But if you look around you'll find some useful posts on DataObjectManager and the gallery.
I got multiple images working on a site I haven't yet made live yet. I like to make a seperate DataObject to handle the images, so I can include captions and fancy stuff. But it might be easier for you to not worry about that to start with.
It'll take some PHP coding on your part, but there is plenty of help around.
If you look in ecommerce/code/products/Product.php on line 28
public static $has_one = array(
'Image' => 'Product_Image'
You'll want many so, change the "has_many" array to include many product images.
public static $has_many = array(
'Variations' => 'ProductVariation',
'Images' => 'Product_Image'
Then you'll need to add a few lines to the getCMSFields function to add a form for you to add mulitple images. This is where I find the DataObjectManager module REALLY useful. If you download it and add it to your site you should be able to add a field like
$MyImageManager= new DataObjectManager(
The next thing will be to print the added images to your template. I think this should work.
<% control Images %>
<% end_control %>