Multiple options - dynamic dropdown list

I have a product that requires the customer choose an option.

Best analogy is the customer needs to specify their preference for something... let's say, color.

The first, valid option is "none", then red, blue, green etc...
The list of options can be huge and will change. I want to drive it dynamically, either via javaScript and a webservice call, or something similar.

Anyone do this before? or does anyone have suggestions?

Thanks

Ok. I've found this and I can work with it.
I can write an external process that will update or re-write a list of variant, attribute values and will update the Nop_ProductVariantAttributeValue table.

So now I have a follow up question.

When you create variant attributes, you name them and assign the display order, and then the dropdown that's created on the product page uses "ProductVariantAttributeValueID" as its "Value".

I'd like to extend Nop_ProductVariantAttributeValue to include a column "Value" and have that used instead. My other option would be to create an intermediate look-up table, but this would be simpler.

Anyone familiar with customizing like this?

My biggest concern is that if I were to change the definition of the table, then it may ripple and break other parts of the cart.