I suggest that you watch this video by webassist:
watch?v=6JBfwp-4B1Y&list=PL1F359A82D04D2329&index=2
it is for a paypal cart, but it shows you a way to deal with options such as sizes, or it could be colours or what ever you need options to be. Wrap the options with the Data Assist show region behaviour from the server behaviours panel... show if options <> 0. If you have no options available, then it will hide everything related to those options.
An example of it in use is here:
store.php
Scroll down the list to see it used in different ways, but it is driven by the same DB column.
I have hidden the add to cart button because the prices have yet to be sorted out, so I don't want people trying to be smug and buy for nothing if you were wondering.
