I have used Feliway spray in the past with some success...that might be the same stuff you already tried, though. You do have my sympathy.

Funny story about one of my boys - the two 6 year olds are part Siamese and part tuxedo cat. The Siamese part is the front half apparently, because they are both very vocal.
Normally my first order of business when I get home from work is to head directly to the bathroom so I can turn on the water faucet for Mikey, who will NOT drink from a bowl. Well a couple of weeks ago I got home and he was not waiting for me by the door. My neice was already home so I assumed she had taken care of him. So I go sit down and start talking to her...about 5 minutes into our conversation from the bathroom - "haaaawhooooa" I had to verify with her that I wasn't crazy and that he had, in fact, just called out "hello". It was quite pathetic...like he was using his dying breath to beg someone to give him a drink.