I'm so sorry to hear your cat is gone.

My (then) 6 year old cat went missing over 2 years ago, I never found her. I asked everyone within 5 blocks in any direction, put up posters everywhere, put up ads on Craigslist, and everything. I didn't learn about the smell thing until after she'd been gone for a year. I'm starting to think my roommate got rid of her because my mom told me he complained all day about her meowing when she went missing, and he's gotten rid of our pets before.

I really hope you find him soon, it's hard losing a pet.