Hey Autocrosser, I failed to remember you are looking for 17s. As you noted, the Alleggerita doesn't come in that size.
Have you tried calling The Tire Rack to let them know what you're looking for? Maybe they have some creative ideas, or know of a company that would be willing to custom drill wheels for you.
One other option is going with a TDR wheel. I
think those are all custom manufactured to specs, including offset and bolt pattern. A couple friends of mine have them and are very happy with them. Cheap and strong. They're not as light as OZs, but probably lighter than OEM by a few pounds.
http://www.avalonmotorsports.com/index.php?main_page=index&cPath=217
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