create dependent options/characteristics

Is there a way to present/enable options based on the selection of an option? For example, I have a product that can be sold unimprinted or imprinted. I would like the imprint options to be available if the customer opts to pay the set up charge (which is my indicator the customer wants the product imprinted). Another example, I have a product with different colors based on the size of the shirt, so selecting a S will show a different list of colors than select a 2XL. The only way I can think of accomplishing this is to have each size shirt, in the previous example, as a separate product or have the same product listed twice--one with imprint option and one without. Unfortunately this seems pretty sloppy and will clutter up the catalog and, more than likely, create confusion.

UPDATE: Ok, for the example where I have colors based on selected size, I can accomplish this task by Manage Variants and 'unpublish' the unsupported combination. Unfortunately, for a product with all sizes and LOTS of colors, this is a huge undertaking but it provides a solution. Thought I'd mention this should someone else be faced with a similar need.