[Plugin: WooCommerce – excelling eCommerce] Custom Quantity Labels

Is there any way to add a custom, descriptive quantity labels to WooCommerce, after the quantity box.

Eg. (try to imagine the product page!):
Quantity: -[ 2 ]+ Mugs

[Add to Cart]
or:
Quantity: -[ 3 ]+ Shirts

[Add to Cart]

Each product variation in the backend would need a field for the label (and another for the singular – Mug or Shirt), and then it needs to be returned in the template. I can do that part I think, and could use Custom Fields for each product, but can’t use Custom Fields for each product Variation…

Many thanks for any guidance!

Edit: I’m using the Canvas theme – if there is a way to do all this without hacking the theme so updates still work etc., that would be good. Maybe using Hooks?