This, my friends, is another example of Virtuemart sadly being a piece of broken software.
Over the past 4 years we have invested heavily in Virtuemart. A few months ago we decided to migrate from VM 1.1.9 to VM 2 to the tune of thousands of dollars. I was forewarned to abandon Virtuemart because it was in a death spiral but because we had so much already invested in the platform I decided to stick with it. However, in hindsight, I should have heeded those warnings and this thread is a perfect example of why. How does something as simple and basic as a customizable drop-down quantity box not make it in the core of VM 2 when it was so clear in VM 1? It's like an auto maker going from a decent vehicle one year to creating a vehicle the next year and not including a rear view mirror; a seemingly small addition that can result in a lot of frustration and headache if it's not there. And now it needs to become an "add-on" better known as a hack. Part of our reasoning for moving to VM 2 was so we would have code that wasn't hacked up. Well so much for that bright idea. Hikashop, Shopify, or even Magento Community is looking better by the day.
-Rainman