Go to
http://car-parts.com
You can find literarly anything for any car there. Everything from navigation parts, engines, body parts, and everything in between can be found there.
Its a website that salvage yards from all over the country use. Yards list parts for sale, costs, addresses, and contact information. They usually ship via UPS and I've even been able to bargain with them to get parts cheaper than they've listed on the website.
(I recently bought a navigation screen for $200. It was originally listed for $400.)
I should also mention that the only differences between the I30 and I35 (body-wise) are the front grille, and and the silver bar that says Infiniti above the license plate. Interior parts might be slightly different, but all parts, inside and out should be interchangeable.
Good Luck!-Zach