127241 ajax category selection

We need someone to come up with an idea to allow users to refine a category selction from an infinite amount of nested categories. This is similar to ebay where you choose your first category, the second box is updated, you choose a sub category, the third box is updated and you choose a third, etc. We require a very similar functionality. What we are looking for is that after the user selects his first category, a second select menu appears below the first with a list of sub categories. He can then choose a sub category from this drop down menu. If he does choose another, a third menu will appear below showing the sub-categories of that subcategory. This process should continue for as long as their are subcategories or the user keeps selecting sub categories. The category list will be attained from our API that we have developed. All you need to pass is the ID of the category and you will receive a list of subcategories in XML format back. The trickiest part of this project will be making sure that the NEWEST select menu has a name of PRD_productCatalog. The preceeding menues can have arbitrary names as its data will not need to be collected. This should be programmed using AJAX so that the page never has to reload. I am not certain that this is the best way to provide this functionality so i am up to suggestions. I am also not confident in my budget as i am not completely sure how hard this will but i do have a general idea. IN ORDER TO BE ACCEPTED, YOU MUST AGREE TO ALL OF THE FOLLOWING: NO ESCROW PAYMENTS. FULL PAYMENTS WILL BE MADE UPON COMPLETION OF THE PROJECT. YOU MUST MAKE AT LEAST ONE PMB POST WITH HOW YOU WILL COMPLETE THIS PROJECT AND HOW LONG IT WILL TAKE YOU. DO NOT INCLUDE REFERENCES TO UNRELATED SITES.