My slightly psychotic black kitty is Cosmo Also, any number of Spanish or Italian male names suit the bill : Rodrigo, Massimo, etc.
Elmo, Gizmo, Gonzo, Bingo, Sanyo, Elio, Zorro, Operaman-o. I think I’m out.
Sorry if I have repeated anyone else’s suggestions, I get going and it’s hard to stop.
Nope, I got more:
Jojo, Cheeto, Frito, Bandito, Tomato, Potato, Clamato, Bono.
I really better get back to work. Damn you, faithfool, you got me started!
Tito
Speaking of Shakespeare, Benevolio and Malvolio.
If he has one paw a different color than the other three, Mano.
–Cliffy
Nemo, Ho-Jo, Flo-Jo, J-Lo, Plinko, Pinko, Po-po, Polio, Polo.
I think I have a problem. I’m trying to work, but they keep coming into my head.
Keep 'em coming. These’ll have to last me unto my old age, when I’ll undoubtedly become the Crazy Cat Lady with 400 gazillion. 
Favorites thus far…
[ul]
[li]Donatello[/li][li]Harpo[/li][li][Poco] Loco[/li][li]Marco Polo[/li][li]Tobacco – which I read as Tobasco, that I even lik better – eww! nicotine :o [/li][li]Pogo[/li][li]Rollo[/li][li]Amino[/li][li]Tokyo[/li][li]Piccilo[/li][li]Placido[/li][li]Placebo[/li][li]Bravo[/li][li]Lingo[/li][li]Pepto[/li][li]Ego [/li][li]Avacado[/li][li]Uhoh[/li][li]Mayo[/li][li]Gyro[/li][li]Petruchio[/li][li]Banquo[/li][li]Othello[/li][li]Iago[/li][li]Lego[/li][li][New] Mexico – my dream place to live[/li][li]Cosmo[/li][/ul]
(Although, I wanna stay as unique as possible. Of course. And a few maybe too tame. I’ve also thought of Mondo, Gonzo (in rememberance of HST) and Garbo.)
I just didn’t realize there was so damn many, and so quickly at that. Pehaps I should start a website just devoted to the “O” ending. :eek:
Whew!! I’m thinking I should give something for the top three that I love mostest. I’ll ponder that and come up with a deadline. Thanks again!
Oooooh ultrafilter, howzabout Shinto (from your Wiki source)? That’s too cool. Then Duke of Rat, that’s just wrong. 
Ohio The state or the japanese word.
Hello, kitty.
Hey, remember that employment thingie-ma-bob? [ul]
[li]Sanyo[/li][li]Zorro[/li][li]Cheeto[/li][li]Clamato[/li][li]Malvolio – Bwahahaha![/li][li]Ohio[/li][/ul]
Gizmo is taken by a friend’s little rat-type dog. I think Bingo is too, but I’m not sure. Also, I know there are more celebrities out there that I’m forgetting. Anyone able to help with those? Without losing internet privaledges at work. 
Lastly (this time), Tito, Whacko and Jacko all remind me of the siblings from another planet. I’ll be steering clear of those lest my someday new cat takes an unsettingly and unhealthy liking to kittens.
“Come here my pretty. Would you like some milk?”
I’m begining to lose touch with reality:
Electro, Micro, Info, Magglio, Otto, Auto, Audio, Radio, gigalo, Telco, Wilco, Lobo, Lipo.
Please make the words stop.
Ze goggles, zey do nothing!
Magneto, Bizarro, Rojo (red in spanish), Taco, Paco.
Someone, please shoot me. I’m seeing words everywhere. And they all end in -o.
photo
foto
choco
yo-yo
pro
Cheating but mello, or yello might work.
Jello?
Brilo
go
gogo
Leo
mio
Dynamo!!
Amantiado (sp?)…Monty for short.
Esperanto
Tonto
Otto <---- a personal favorite
Lion-O or Panthro (from Thundercats)?
My cat’s name was Popocatepetl, but we usually just called him Popo.
What about Daddio for a real hep cat?
Machismo
Hesalto
Diablo (for evil kitties)
Tevalvo
Voloodoo
Amerigo
Gaspatcho
Naming a cat after a religious tradition seems a bit odd to me, but hey, go for it if you like it.
Macro, Studio, Undo & Redo (great for two identical cats), Mofo, Mojo JoJo, Cisco, Mono, Stereo, Hilo.
Now I know what an addict feels like. I feel rock bottom coming anytime now.