@margo,
Somehow, I was expecting you Margo. If it is he, I suspect he got scared of all the stuff going on while I was hospitalized, and took off for parts unknown. Now, I've seen someone like him a block away, but he was unapproachable. Barney was a handsome and good looking cat and probably found a home nearby. It's possible his new family moved away while he was out and about. I'm not going to steal him back, of course, but if he wants a home here, or just a cheap meal in the evening, that's fine too - even if it isn't really Barney.
He was last in the house for sure in late April of 2007. Might just be a good looking stray riding the grub line. He certainly doesn't have memories of me.