Servals are the most widely domesticated 'wild' cat species. I have a friend who breeds them and keeps them in his house just like his regular cats. They can be litter-box trained, easily trained to walk on a leash and when socialized as a kitten, they really adore human company. As adults they may scent-mark, but spaying/neutering can help stop this behavior altogether.
I know those of you who believe "wild animals belong in the wild" are probably furious right now, but I hate to tell you guys that servals make wonderful pets for those who do proper research and raise them correctly (just like with wolfdogs or any other animal).
Check this site out (although, be aware, you will see pictures of servals, caracals, bobcats and lynxes all being raise together in the same home as pets. So if this seems 'sick and wrong' to you, then don't view this site!!!)
http://www.noahfcc.com/servals.htmPhotos below:
House-raised serval cuddling with regular kitten.

Captive-bred Domestic serval kittens.

Unfortunately, many states in the US prohibit ownership of what the gov't deems a 'wild feline'. I don't live in a state where ownership of these golden beauties is legal. But if I did, you can bet I'd have one in my house with my wolves!
They also come in melanistic form:
