I'm not sure if there's a clearly defined site where you can find all the look-alikes, but I have a few here that might be helpful (not that I've really been looking out for any look-alikes, but I thought this topic was interesting and so I did a quick search on Google).
So there's Suzaku Kururugi from 'Code Geass', Hiro from 'Soul Eater' and Takuma Ichijo from 'Vampire Knight' to name a few. That's what some sites said, anyway, so yeah, not too sure about them myself... ^^;
I'm sorry to go into this conversation, but Ragnelle, if you want, theres's a online game called 'Star Project' which the main character name is "Touya" which shares some looks with Tamaki, just except the eye color. The online game characters looks like some of the Host Club Members too ~
Try going to www. deviantart. com. There are many fantastic pieces of fan-produced art there and if you "search" tamaki lookalikes, you may find what you're seeking. If not, it's just a really cool place to browse images.